How Can I Find a 1mb Photo for 2k Upload

Resolution and File Size

In this lesson we await at issues of resolution and file size. Understanding this is very of import if you are going to consistently deliver the right image size to different markets.

Introduction
Resolution
File Size
Image Size Panel
File Size 'Dominion of Pollex'
Prototype Interpolation
File Size and Pinch
What to Deliver

Introduction

Pixels take no gear up size, they just aggrandize or contract to fill up the infinite available. Below the same epitome is shown twice, both times at the aforementioned image or document size. But each copy is made up of a different number of pixels which only expand in size to fit the image size. So while both 'epitome sizes' may be the same, the resolution of each is conspicuously different.

Figure oneThis image is made up of 1200 x 800 pixels and looks to the eye similar a scene might look in reality.

The aim is to have plenty pixels, which when resized to fit the image size, are smaller than the monitor or printer dots. The paradigm above has a pixel size smaller than the monitor dots and so looks expert. The moving picture below has too few pixels so have resized to the indicate where the pixels are larger than the monitor dots and the epitome looks either bad, or even useless as in the 12 ten eight pixels image.

Figure 2Although diddled upwards to the same size as the previous image, this paradigm is made up of merely 120 x fourscore pixels and now nosotros are starting to see the actual pixels, which is called 'pixelation.'

Below are the same images as before but resized and then that the pixel resolution is 72  dpi to suit the monitor. Since the pixels are now set up to the aforementioned resolution, it is the image, or document size, that shrinks or expands to fit. Both images now have the same resolution, it is now the image size of each that is clearly different.

Figure 3Here the same two images are at present set to the aforementioned resolution. While both expect proficient now, what differs is the size at which the image is displayed. The smaller prototype only has plenty pixels to display well at that size.

This ways that when talking most the working file size of an image it is not plenty to only state the resolution or image size by itself. Both resolution and prototype size demand to be used together.

Resolution

So often people speak about a 300 dpi image equally beingness a quality image. Merely what do they mean by a '300 dpi' image? This is rather like someone request you how far is it from Abuja to Lagos and y'all answer '70 kilometers per hour'. They would look at you lot funny. That is because you only told them half of the answer. Yes information technology may exist 70 kilometers per hour, but y'all need to tell them for how many hours.

This is the same as someone saying, 'Oh, simply give me a 300 dpi prototype'. What they have told you is that they want each inch of your image to have 300 dots, simply they haven't told you how many inches they want the paradigm to exist. It is the number of pixels in an epitome that determine file size; resolution by itself is not enough.

Effigy 4This is i inch of the image beneath. DPI ways 'dots per inch' but you need to know how many inches to know the file size of an prototype. Merely giving the resolution is not good enough.

Figure 5Higher up is the full image. The prototype is conspicuously more than than but 1 inch square. And so to sympathise the file size you lot demand to know both the resolution (300 dpi) and the reproduction size (8 inches loftier by 12 inches wide, for instance).

So when an editor or a designer is asking you for an image and they say, "just ship me a 300 dpi image", you need to enquire, "300 dpi at what dimensions?" In other words, at what height and breadth?

File Size

There is actually an easier way to ask the editor what he really wants and that has to practice with file size. This is much the same way that if someone asked y'all the distance between Abuja and Lagos information technology would be easier to answer, '700 kilometers'.

Figure half dozenAn A4 grayscale image at 300 dpi is calculated below at viii.half-dozen MB in size. In reality it is closer to 8.7 MB simply because the dimensions of an A4 page are larger than eight x 12 inches.

To come across how the file size is calculated, accept the image above every bit an example and assume that it is A4 at 300  dpi. To simplify it let'due south assume that is 8 inches  10 12 inches.

File size is determined by the number of pixels so the aim is to find out how many pixels the image contains. Since the resolution is 300 dpi, it means that each inch is 300 pixels across. As the prototype is 8 inches wide that ways there are 2,400 pixels in width (8 ten 300). Likewise, as the epitome is 12 inches long, the image is 3,600 pixels in length (12 x 300). To get the total we multiply the breadth by the length and the reply is viii,640,000 pixels (2400 x 3600).

We at present know how many pixels are in the prototype. So how do we become to file size. Well this is a grayscale epitome and we know from the section on image pixels that for a grayscale image each pixel is 8 bits or i byte in file size. So in total the A4 epitome of viii,640,000 pixels has a file size of eight,640,000 bytes or about 8.2 MB (this is because there are 1024 bytes in a kilobyte and 1024 kilobytes in a MB).

So information technology would be a whole lot easier if your editor asking you lot for an paradigm big enough to fit the size he wants to print it at asked y'all for an 8 MB grayscale image. Or if he wanted it in RGB colour he would multiply that figure by three and ask you lot for a 24 MB image.

Notation:  While information technology is simplest to accept but ane unit of measurement, such every bit everything measured in either inches or centimetres, it is still common in some countries to use a mix of the two. Often newspaper sizes are measured in millimetres by using 'A' sizes, simply image resolution is yet quoted as 'Dots per Inch'. This is inconvenient equally it requires measurements to be converted at times, but you lot will just have to be put up with this until full metrification becomes standard.

Image Size Console

It is not necessary to calculate the file size exactly every fourth dimension. Photoshop has an Paradigm Size console that can be used as a reckoner. The panel can not be accessed without an image being opened, so create a new paradigm first (Ctrl+North) choosing the colour mode needed (RGB, CMYK, Grayscale, etc).  Make sure the 'Constrain Proportions' box is unticked to allow width and height to be separate, and that the 'Resample Epitome' box is ticked to allow the resolution to be separate every bit well. At present figures tin be entered into the Document Size (highlighted) with the file size appearing at the top of the palette (indicated).

Figure 7The epitome size palette provides an accurate way of calculating the size of a digital image you have opened in Photoshop.

File Size 'Rule of Thumb'

You aren't always in front end of a computer when yous need to calculate paradigm size though. So it is really helpful to have a dominion of thumb that guides you. Just retrieve of an A4 as 24 Mb for an RGB colour, 8 fleck image at 300dpi. The beauty of the number 24 is that information technology is and so divisible, and therefore easy to summate file sizes. Accept a piece of A4 paper and write '24 on it.  Fold it in half and write 12, fold again and write 6, then fold once more and write 3. Well-nigh all the images yous utilize will fit one of these sizes. So the side by side time you are asked what file size is need for a quarter page RGB photo, fold an A4 twice to requite you half-dozen Mb.

Figure 8The illustration above shows a quick manner of computing the file size of an RGB image needed for printing an A4, A5, A6 and A7 epitome.

A grayscale is i third of an RGB so write eight,4,ii,1 instead. For a CMYK prototype write 32,16,8,iv as information technology has 1 actress aqueduct. If the image is 16 chip and then double the figures. In this way, wherever yous are y'all can impress your editors or clients past a speedy calculation of what file size they need.

Note: The figures used higher up are not verbal, only they are easily divisable round numbers that allow you to rapidly calculate the rough epitome file size required.

Prototype Interpolation

If you need to have a larger file size than was provided by the digital photographic camera or scanner, then Photoshop tin create the extra pixels. Simply this does come at a cost. On the right is an image that was one tenth the paradigm size of that on the left. It was then interpolated 10-fold (ane,000 %) to bring it upwardly to the same dimensions. While at that place is zippo to cease you lot resizing an paradigm this style, exist aware that Photoshop has no reference to what the original unscanned image looked similar and therefore has to 'invent' the extra pixels. An increase of several percentage will not be noticed, just the more the resizing, the softer the paradigm will become.

Figure 9The prototype on the left is the original quality. The one on the right was reduced to a 10th the size and then interpolated upwardly in Photoshop to the same size. You lot can meet how soft the image becomes equally Photoshop simply invents pixels and blurs all edges.

The best solution is to exercise the scan again at the correct size. But if rescanning is not possible then in that location are some different interpolation methods to help with the problem. Genuine Fractals is one such program that allows significant interpolation without meaning loss of quality.

File Size and Compression

At this stage it needs to be mentioned that an image can have several types of file size:

The Camera Raw file has a size, only this will be dealt with afterward.

The Epitome converted from a Camera Raw file, or scanned from film, has a different file size.

You may and then ingather the image to reduce the file size, or employ interpolation to increment the file size.

For the sake of simplicity, let us only deal with the finished image after you have shot it, converted it, and done any cropping. This image, when opened in Photoshop, has an "open up" or "working" file size, equally seen in the Epitome Size Panel department above. However, when yous come to relieve the finished paradigm you will take to determine most file compression.  Usually yous volition be relieve the image either every bit a TIFF file, which can have pinch or none at all, or every bit a JPEG file, which volition always have compression.  If the prototype has been saved with compression then you notice that the save image has a much smaller file size than what it was when it was open.  Remember of this as "saved" or "compressed" file size.

The problem comes when yous wait at an image that has been stored on your hard disk and you need to decide what the "open up" or "working" file size is equally it is the "open up" file size that counts when you accept to send an prototype to a client.  If the file is a JPEG then you know already that it is compressed, but if information technology is a TIFF then you may not know if compression was used.

As an instance:

Figure ten The paradigm details as seen in Windows 7

Viewing the prototype details in the file browser it can be seen that the file size is listed every bit 1,178Kb.  As this is a JPEG file it means that this is the compressed size, so the all of import "open" file size must be a lot bigger.

Figure xi The image 'properties' equally seen in Windows 7

Looking at the file 'properties' will show that the image has dimentions of 2336 x 3504 pixels.

NOTE:  The style that the above information is displayed will vary between Mac and PC computers.

Figure 12 The image details as seen in an image browser

Usually this data can likewise exist viewed in Span, or which-ever image browser software yous are using.  Again the dimensions are given as 2336 x 3504 pixels, and that it is a 24 chip RGB image. The full number of pixels is 2,336 x three,504 = 8,185,344 pixels.  Now if this was a grayscale image that would hateful that the image is 8,185,344 bytes in size, every bit each pixel equals i byte.  Withal, as the image is a 24-bit RGB file, significant that each color channel is 8 bits, and therefore i byte each, and then the RGB file size is eight,185,344 x 3 = 24,556,032 bytes.

24,556,032 bytes / 1024 = 23,980.5 kilo bytes

23,980.5 kilo bytes / 1024 = 23.418 mega bytes

By now you lot will have probably concluded that this is a little painful, to put information technology mildly!

Figure thirteen The prototype opened in Photoshop

A much easier manner is to merely open the image in Photoshop...

Figure 14 The "open" file size is given at the top of the panel

...then open the Image Size panel (Image > Epitome Size on the menu bar).  At the superlative is shown the "open" file size, 23.4Mb in this example.

The main betoken here is that in that location is a clear difference in file size between the "compressed" size on disk of merely over 1Mb, and the "open" or "working" file size of over 23Mb.  So unless you like the idea of torturing yourself with a lot of needless calculation then just open the image in Photoshop and let it do the piece of work.

NOTE:  If you take a lot of images that you need to audit for their working file sizes, and so there is JavaScript that can run through a whole folder of files and create a spreadsheet that lists the compressed and open file sizes for you.

What to Deliver

E'er bank check to meet if the customer has a set listing of standards, and always follow that.  Usually that volition be images saved at 300 dpi, unless they are only intended for the web where the common resolution is 72 dpi.

File size requirements, that is "open" file size requirements, will vary from client to customer, but expect that the minimum size to exist 24 Mb for RGB images.  Nevertheless, this can be lower for newspapers and will almost ever be higher for picture libraries.

RULE #one:  ALWAYS follow the supplied set standards.  Clients will oft reject piece of work that does not meets the required standards, with a resulting loss of income for y'all.

Dominion #2:  Don't get defenseless in the trap of supplying the images at different working file sizes to fit the layout requirements of a particular chore.  That is the responsablity of the designer, inless of course they are willing to pay yous extra for doing the work.

Note:  Get in the habit of saying "open file size" or "working file size", and "saved file size" or "compressed file size", and not just using the vague term "file size".  This can save a lot of confussion when dealing with clients.

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Source: http://shutha.org/node/796

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