Image Optimisation
File Types
When compressing images for the web, there are two methods that are commonly used:- JPG - used for photographic images that consist of lots of tones and colours.
- GIF - used for illustration, block colour images and animation. Should be used for heading images as it produces sharper results than JPEG compression. GIF compression also supports simple animation and transparency.
- SWF – Used for Macromedia Flash animation. Commonly used for online ads, and applications. This format should also follow the compression and file size standards when optimising for the web.
You must ensure a flash detector is used when using SWF files for qantas.com. The flash detector is to be included in the header. Also a substitute GIF image should be created for a flash file.
Note: In the creation of SWF files, importing images for use in the PNG image format can be a lighter file alternative to using a GIF or JPEG. Converting GIF images to PNG will typically yield about a 10% improvement in file size (and thus load time).
File Size (Weight)
- Standard image graphics should be about 4K in size. 10k maximum.
- All images should be optimised for display on the web. Use the appropriate compression scheme to achieve the appropriate results for your image eg. GIF & JPEG
Image Dimensions and Styles
For information on image dimensions and styles go to the relevant image section, for these specifications.