Viewing the actual XPM data in GVIM
From Vim Tips Wiki
created 2001 · complexity basic · author Carl Lunde · version 6.0
Gvim has an excellent syntax highlighting for XPM images, but sometimes it's useful to view the actual data. This can be achieved by searching for everything, type in "/." and all characters will be highlighted and therefore the old colouring is lost. To regain the normal highlighting you can search for a non-existent sequence, like "/foo".
This requires search highlighting to be turned on, see VimTip14 (or just type :set hlsearch). It should also work with 5.7
Instead of searching for something nonexistant like /foo, just type :noh (for no highlighting)