This application is very simple and easy to use. It has a drag&drop interface where you can insert all file types. It provides a text field where you can insert your md5 value and compare rapidly with md5 value generated from file. It is based on terminal's md5 function.
All picture file, pdf, html, txt are fully supported from first version.
InstantMD5Checksum is compatible with Mac OS X 10.6+ with 64-bit mode.
See changelog: https://sourceforge.net/p/instantmd5check/wiki/Changelog/