File Sizes Explained

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How to take photos: Understanding File Sizes

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> 56k WARNING

Basic gear you need:

A computer, a picture processing software program, and about ten minutes of your precious life

The Aim:

	To keep the original photo, unchanged to be like your negative for film
	To create a small file, that can be e-mailed
	To understand why big files will lose you e-mail friends

Software Suggestions (listed from more expensive to cheaper)

	Photoshop CS3 (ultra expensive; for professionals)
	Genuine Fractals (expensive; for professionals)
	Photoshop Elements (sort of expensive; for high-end amateurs, and me)
	GIMP (Free; apparently at professional level, but...)
	Picasa (free download from Google; for family use)

The Explanation:

These are screen shots from my computer. These contain two files from the same picture. One is the full-sized jpeg file, and the other is much smaller, and is e-mail friendly.

Larger files let us print good quality photos onto paper. The large one of the two here can be printed nicely on paper sizes up to 106cm by 70cm (41" by 27"). However, the smaller, to retain the same quality, would be printed at 4cm by 2cm (2" by 1"). Can you see which is which?

Still don't know? Well, let's (left) click (once) on the picture on the left first.

So... What's small then? Well, let's click (once) on the other picture and see.

But hang on, they LOOK the same! Well, what you're seeing here are called 'thumbnails', which are only a preview of what is inside the file. Like reading a car catalogue, the pictures aren't life-sized (luckily).

What I did was resize one, and saved it with a slightly different name; I added 'sm' for small (my own code letters). Since I often work with variations I called the other one LG... can you break my little code?

Anyway, why need a smaller one for e-mailing? Well, can you imagine receiving a car catalogue which provides actual-size pictures of cars? That would crush your mailbox! And can you imagine the poor boy who has to deliver it? So, we make the pictures smaller, so the catalogue can easily fit into your mail box. It's the same sort of concept in digital; see the analogy in the pictures below.

Click on these to view at a larger size:

Printing size E-mailing size (Use full / printing size for photobook)

How do you make a smaller one:

For this, we'll use Picasa, as it's available free. Click here to get it.

Step 1. Open Picasa and (left) mouse click once on your chosen picture (below)

Step 2. Click once on 'Export'

Step 3. You'll see this dialogue box (below)

	1. Choose 'My Pictures' as your destination folder
	2. Use the sliding scale (left mouse button) and move it until you see the number '480'
	3. It's perhaps wisest to select 'Normal' for image quality
	4. Press 'OK', then Bob's your uncle. It should also automatically open the file it was just 'exported' to.

Step 4. To e-mail. The picture to the right, is the full size of my monitor, but luckily for you, I've thumb-nailed it. Click on it to see how to e-mail it. (Be patient, it's large!)
Other programs (like Adobe PhotoShop):

They're mostly easier.

	1. Open the program, go to 'File', go to 'Open', and find the picture you want to edit
	2. Find something called 'Image Size' and select it
	3. Adjust the image size to about 500pixels on the longest dimension (usually width). Note, if you see 'Canvas Size' or have it, it has a slightly different function (it trims your 'canvas'), don't get them mixed up.
	4. Press 'OK'
	5. Go to 'File', go to 'Save As', and add 'sm' to the file name, so you don't overwrite (replace) the original. And again, Bob's your uncle.
	6. For e-mailing, refer to 'Step 4' thumbnail above