I need a free and preferrably open source image coverter or editor.

covert bmp file to jpg, jpg to bmp, tiff to jpg, etc etc etc.

Must have "batch conversion" function because It'll be really stupid to convert the image one by one when you have 100 of pics.

I want to compress my BMP collection to smaller sized jpg files becoz it's eating up space.

juz do a search on download.com
u can use faststone, irfanview, paint.net...even picassa!!
nowadays ppl r so lazy to search

I have already done a search lah, my searching skill not so good u know.

all the results are non free software.

vso image resizer for convert

google picasa for both function

I'm recommending Irfanview, again. It's freeware and fits your requirement plus screenshot manager, image viewer and editor, and more... in a little 1.3MB package

Here's a screenshot of Irfanview capability of doing batch renaming/conversion
http://forum.lowyat.net/index.php?act=Atta...=post&id=744586

u can try this freeware..faststone image viewer

http://www.faststone.org/FSViewerDetail.htm

use irfanview, you'll be surprised at the batch conversion options.