Hi
If the files you want aren't in the Recycle Bin, the most important thing to improve their chances of recovery, is to stop using the drive letter where they were saved. If you've already used it extensively, saving large files to it, then the pictures have probably been overwritten. On the other hand, if the pictures were on drive E, F or G for example and you've only been using drives C and D since deleting them, then they might be recoverable. Bear in mind that drive C is constantly used by Windows itself, so you can forget it if that's where they were saved.
Suites which include a recovery program (called Undelete) are Symantec's "Norton Utilities" and also "SystemWorks". You can get old editions of these cheap on eBay, get a version that is compatible with your version of Windows! Beware that the act of installing a new program causes parts of the disc to be overwritten (with the new program) - but that's OK so long as you're installing it on a drive letter OTHER THAN the one where the pictures you want to recover are.
Best Wishes
SS, November 2007