Ruby library for finding the size or type of image with minimal dependency

 FastImage does this minimal fetch for image types GIF, JPEG, PNG, TIFF,
 BMP and PSD.
 .
 And it doesn't rely on installing external libraries such as RMagick
 (which relies on ImageMagick or GraphicsMagick) or ImageScience (which
 relies on FreeImage).
 .
 You only need supply the uri, and FastImage will do the rest.