how do i change it to .png

Open it in an image editor like GIMP then save it as .png

but u see gimp wont take it

You don't have to use Photobucket. www.tinypic.com is more flexible and will probably help you.

Another way, pretend I made an image called "Oshit.Bmp" To change it's format edit the title and change the ".Bmp" in the name to ".Png" Or ".Jpg". It should then say something like "would you like to change the format?" and click Okay. Then go to imageshack (or photobucket, or tinypic) and upload it. I've done it on mac but it should work on pc too.

EDIT: You usually can click once to select the file then click the text a few seconds later to rename it.

i know how to rename it but gimp wont take it so i cant rename it

Then use paint . Just right click on the image > Open with > Paint > Save as (or save) > (name here).png > http://imageshack.us/ > upload it there > then just copy and paste the pic's link in message like this

Why do you need to be on Gimp? I'm talking about just renaming the attachment on your desktop.