How do I get rid of everything?

I am trying to delete all photos from my iMac in one swoop before I take it back for exchange tomorrow.
How do I do that?

Open up Finder, select 'All Images,' and delete them?

Perhaps a wiping clean of the system is in order. Backup everything, then pop in the restore discs and restart the computer. Zero out the drive using Disk Utility, and then do an Erase and Install. It'll wipe any trace of your personal files.

Thanks, does it take long? I want to do a few things tonite.

Zeroing out the drive is probably the part that's going to take the longest as it literally rewrites every sector on the hard drive to make sure nothing is left behind. You could always skip this step and just do an Erase and Install as it would require somebody who knows what he/she were doing in order to get at those files on the hard drive.