lost photos on IPAD after a factory reset

Sign in with your Apple ID - https://support.apple.com/HT204053

This is assuming you were using:

Keep your photos safely stored and up to date on all of your devices - iCloud Photo Library - https://support.apple.com/HT201313

If you wiped the device and did not back up photos in iCloud or with iTunes then they are gone. There is no internal backup and I have never heard of being able to recover items using a third party tool once erased. If that were possible you could bet there would be a huge uproar about Apple security on the web.

As Limnos has already stated.

If you did a complete Erase All Contents and Settings of your iPad and you didn't back up the data on that iPad before you did this, any data, including photos, is gone for good. Your photoslimages are gone and gone forever.

“Erase All Contents” means EVRFYTHING get erased off of the device, permanently.

That iPad ends up being the way it was when it was new and still in the box.

Your photos/images have been permanently erased. Thd photo/images are gone.

Sorry.

Don't ever perform a complete factory reset of any mobile computing device or computer until you have established a backup of all of the data from those devices.