image resolution compressor on upload

i need my image uploader (functional) to be altered so that it can receive images of any size, but once uploaded they are compressed to a small resolution so that all images on my server are around 50KB. i'd like this script installed so that i can pass all images through a resolution cruncher, and watermark (if desired). the project must be completed within two days from start, as this is a simple install of script, which i cannot seem to find