Why do not use image files in grid ? The images downloaded everytime.

When I use AW.Templates.Combo and AW.Templates.Checkbox in grid contol, the images are downloaded everytime.
What kind of plan do you have to solve it?
For example, you will change grid control to use fixed image files. etc...

If this is IE you are refering to it is probably a corrupt cache on that machine.

Easiest way to fix it is move the cache or have a look in the ms knowledge base

There is no difference if the image file is referenced by CSS or its separate <img> tag. There is however a known bug in IE that it could request the same image multiple times if the image reference is created dynamically by javascript. To fix this you have to 1). make sure your webserver sends correct cache-control (for IE) and expires (for FF) headers and 2). preload images. To simplify preloading it is actually much more efficient to put multiple small images into single 'image library' file and later refer to parts of this large composite image with CSS rules -

http://www.activewidgets.com/grid.howto.cells/images.html

Just want to add that you need to preload images only during the first visit - aftewards the images are already in cache and will be loaded from cache as long as specified by your cache-control/expires headers.