I think the icons are made when the EBOOT is assymbled (meaning the maker of the homebrew, not you, decides what the icon will be if any). You can move all the corrupted icons to the bottom by connecting the psp to your computer and selecting all the files with the %, then right click and cut them (not copy), paste them to the desk top of you comp, then select them on the comp and paste them back to the psp. The files are listed by creation date and this will give them a more recent creation date so they will be on top of the corrupted icons.
You can also go to
www.pspbrew.com and when you download your brew from there, they have an option to hide corrupted icons...