1. Is there an average background image size (dimensions) that I can use a template for my site? I have a fairly large background image that may not need to be as big as it is...
Good question. Generally I recomemnd against large background image for just this reason. Some great designs have a 1px x 1px background image but any larger than that is difficult. Can you tell is more?
2. What is the standard procedure to otimizing images to decrease page load times? So far I know to:
- save as png with no transparency
- crop as much blank space away from images
- Use this tool:
www.webresizer.com/
Yes, that's all good advice for .pngs, although often a .png is chosen because it does transparency well and can easily work on colored background.
.jpgs are at least as popular and they have their own set of optimization needs.
What is this talk about alt tags for images?
It provides information about the image to two types of visitor who can't see images:
1) search engines
2) partially-sighted people
It's good to be nice to both groups and add an alt tag.