ConvertKit

Convert video files (every video file that ffmpeg supports) to the following: MP4, AVI, MOV, WMV, MKV, M2V, OGG, FLV (or extract audio to the following formats WAV or MP3)
Convert audio files (every audio file that ffmpeg supports) to the following: MP3, WAV, FLAC, WMA or OGA
Convert images from various raw or normal formats to JPEG, PNG, TIFF, BMP, GIF, ICO.
You can also rotate video and image files. There is a simple "How to" guide, but I hope the application is so easy to use, that you will not even need it.