afterimage.vim
Edit ICO, PNG, and GIF icons. No really. They're converted with ImageMagick to XPM, a plain text image format with beautiful syntax highlighting in GUI versions of Vim. Here, it's easier just to show you:
And yes, I did say edit. Obviously you're not going to be uninstalling Photoshop anytime soon, but for stupid simple tweaks, it gets the job done.
Oh, and it can also handle PDFs (with pdftk), Word Documents (read-only, with Antiword), and Mac OS X plist files.
Installation
If you don't have a preferred installation method, I recommend installing pathogen.vim, and then simply copy and paste:
cd ~/.vim/bundle
git clone git://github.com/tpope/vim-afterimage.git
Once help tags have been generated, you can view the manual with
:help afterimage
.
Contributing
See the contribution guidelines for pathogen.vim.
Self-Promotion
Like afterimage.vim? Follow the repository on GitHub and vote for it on vim.org. And if you're feeling especially charitable, follow tpope on Twitter and GitHub.
License
Copyright (c) Tim Pope. Distributed under the same terms as Vim itself.
See :help license
.