Wetlook World Forum

The trick with JPEG images is setting the lowest possible image quality setting before the image becomes visibly damaged, or even permitting damage if it's only a sample. There's little point using a quality setting where the extra quality isn't even perceptible. I have no software on my PC capable of doing this (I'd have to cart all the files over to the Mac for that) so I've settled on what seems to be a reasonable quality setting. I keep image subsampling on (keeps the file size down) unless the image contains a lot of red, which chroma subsampling tends to destroy.

Two mistakes that many people make, are excessive quality (cameras tend to keep the quality high for safety), and non-Web-safe images: images that contain all manner of rubbish embedded in the image. Photoshop is terrible at bloating images with nonsense data like XML. Make sure that "Save for Web" is ticked when saving any images for the Web, to strip out all extra data.

I went through all the banners Steve had collected for his Links page, and resaved them all from JPEG back to JPEG. I took a huge slice off the size of the files: so many of them were saved with too much quality and probably useless data inside as well. Some were dimensionally too large, and being squashed into a small area on the screen, again, pointless.

Most people just don't have the understanding they need of image compression, or the realisation of how much it matters to dial-up users and their own site traffic! Image optimisation is almost an art form unto itself. Each image type (screenshots, photos, diagrams etc) and image format (JPEG, PNG, GIF, SVG etc) has its own optimisation strategies.