When saving an image, what is it best to be saved as, .gif, .jpg, .jpeg, .bmp, .art or other? What's the differences between all of these? Doesn't saving it as .gif shorten the images load time or something? Which works best for the web? .gif files only for animation? Any answers to these would be helpful, thanks
.PNG is the newest and it is a non lossy format. Meaning it suffers very little or zero loss when viewed or saved or optimised. PNG format doesnt work in old browers....maybe earlier to win98 which is almost obsolete]
JPG is the most lossy format which suffers in quality if you try to optimise it. Dont know much about gif cos I never use them. Yes as you say it is used in animated images.
Image files also contain a lot of useless date inserted by the editor making it thick. It can be cleaned up using a image cleaning tool.
Optimisation is also a way of cleaning up a image file without loosing much of the visible image quality. Too much optimisation can reduce the quality and too little can mean a large file . It has to be some compromise inbetween.
For high resolution images dont optimise it but instead give a small/medium thumbnail image and the large image in a pop up window.
visit a image stock website and check out how they use it on their webpages.