ZF-3907: Add a filter to automatic change the imagetype of a file

Description

Add a filter which can change the imagetype.

It should be able to change PNG, JPG, GIF and so on to the other format. Look if it's even possible.

Comments

Bulk change of all issues last updated before 1st January 2010 as "Won't Fix".

Feel free to re-open and provide a patch if you want to fix this issue.