The rule of thumb is to try to keep file sizes as small as possible. You can easily resize photos in any graphics program (Windows Paint can be found in every Windows system). Absolutely do not go to megabytes (“MB”) with your photo sizes, keep them at a maximum of a few hundred kilobytes (“KB”) per image. If you have many photos, consider making them even smaller. Remember that only 5 photos with the size of 200 KB each make one megabyte, and those are only your photos.
If you use web graphics, such as buttons and dividers, choose the GIF format. Web graphics in GIF format are smaller in size than JPEGs, and GIF also allows transparency. Consider using web graphics carefully, though. Are they absolutely necessary for your particular site, do they add something and are they well made? Grainy, distorted graphics in all colors of the rainbow will only make your page look amateurish. If you want to use web graphics, find ones that fit your overall color scheme without jumping on the eye.
You have likely seen animations (animated graphics) offered for free all around the internet. If your site is personal, well-designed and loads fast, sure, why not use a few if you like them (but check file sizes). If your site is a business, never under any circumstances use cheap web animations, not even for the “Contact Us” icon. They will eat away the professional air of your site.
Monitor resolution
If you have a newer computer, your monitor resolution is likely set to 1024x768, or bigger. However, keep in mind that recent polls show that many people still surf with a monitor resolution of 800x600. Design your site to look good with that resolution, and it will also work for the bigger ones. If you design only for the larger resolutions, your visitors surfing with the smaller size have to do a lot of scrolling, not only up and down, but left and right as well.