SublimeMagick uses the identify tool of ImageMagick to show properties of images on status bar.
Latest commit b17800b Nov 12, 2013 @Kentzo Merge pull request #3 from Matthewnie/master
Updated to work with Sublime Text 3

ImageMagick is required.

You can specify custom format by changing the "sublimemagick_format" setting. See SublimeMagick.sublime-settings for details.