Processing images in SRAM(DE2 board)

Your approach of loading the memory with the control panel and then loading in your own design should be fine.

Are you powering down the board before loading your design? Perhaps the problem is with your sram controller logic. Maybe it's doing a clear or a reset perhaps?

Have you considered storing your image data in on-chip memory and either using the initialization file (when using it as an avalon component) or loading your design and trying the in-system memory content editor?

Another approach might be to use the eeprom instead of the sram.