Как отсканировать 500+ игральных карт в png

In my opinion it would be better if you scann them one by one.

This way they will be aligned the same in respect of the corner of the scanner and can be named with a specific file name.

After that you can prepare a Photoshop batch action to crop them and to make the round borders, and as they are all aligned the action will be aplied correctly.

Look for the specific steps you want, but some tutorials can be found arround: https://www.google.com.mx/search?q=batch+action+photoshop

And here is one for Photoshop esentials for the rounded corners, for example http://www.photoshopessentials.com/photo-effects/rounded-corners/

Some time is wasted on a "preview" where you pre scann your image and select the part you want to scann. You can skip this step. Make it only once for the first scann each session.

One recomendation is that you prepare your workspace so you can in some extend do that in a series of optimized arm moves.

One important thing: Deactivate any post process during the scann. For example some scanners have some feature to remove the screen of the print. But this would be applied during each scann making it last longer. Make any de-screening as part of your batch action. This way you can go and see a movie whiloe yhe computer makes this adjustments.

An aditional tip, scann at the real resolution you want. Some people like to use the maximum scanning resolution. Make some tests, probably you can use the standard 300 ppi or probably 200 ppi are just fine for you. But probably scanning with more ppi is just a waste of time.

I was scanning photos from many photo albums and found the software (at the time) that auto crops and straightens the images to cause distortions. I ended up doing a physical hack that made my life easier. Since most of the photos I had were the same size, I made a holder. I went to a craft store and bought a really thick piece of black cardboard. I cut the cardboard to fit my flatbed scanner. Then with a spare piece of cardboard I traced the outline of a 5x7 photo onto it and cut it out. I then placed that cutout onto the flatbed cardboard and using a T-Square, I was able to line up and level the cutout onto it and cut out several 5x7 holes. I was then able to place the photos into the holes and have perfectly level pictures every time. Plus with the cardboard being black, it was easy to select the black in the image, invert the selection and pastes the pictures individually to be saved.

Software might have gotten better at this by now, my current scanner software has the ability to separate multiple photos, but I havent tried it.