Monday, November 13, 2006

Image optimisation and the magic of 'Save for Web'

Firstly, my apologies to my ardent blog-follower of a sister who has not had anything to read for over a week. Sorry Janet - this one's for you!

I'm taking a class on the uses of Photoshop at the moment; it is an amazing piece of software both for professionals and for anyone who likes to play around with pictures. It's not cheap though unfortunately, but it does have a cheaper cousin, 'Photoshop Elements' which works the same way only with a few less features.

One of the main problems I have come across with people wishing to add images to their websites is filesize. Usually when you take a picture with your digital camera and transfer it to your computer, the image has a filesize of about 2MB (that's 2,000,000 bytes). You can't just put that image straight onto a website because that web page will take forever to load - that's if it loads at all.

Try right-clicking on the picture of me above and select 'Properties'. You'll see that picture is 7,773 bytes (or 7kB). Once upon a time that photograph was 2MB, but just by cropping, risizing and using that magic 'Save For Web' option, the image size has been optimised to achieve the right balance between filesize and picture quality.

What about format? Using the right image format can also shave the bytes of your filesize. Here are a few simple tips for shrinking your image filesize, and you don't need expensive software to do it - most of this can be done using microsoft paint.
  • Use GIFs for logo's, line drawings and simple images
  • Use JPEGS for photographs
  • NEVER use bitmaps
  • Check the dimensions are no bigger than necessary
  • Crop out the rubbish
  • Check the resolution (you only need 72ppi - pixels per inch) for the web
  • Reduce the number of colours
  • Be minimalist - a word can tell a thousand pixels

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