Two questions for Photoshop experts

Our devs have a couple of questions for those who use Photoshop extensively.

1. What is the "common sense" of the image size limit to be copied/pasted in Photoshop. Do you commonly copy/paste 7000x7000 px images? 10k x 10k px images? Or are these figures likely to cause hangups and out-of-memory issues, so you prefer to save a 10k x 10k image into a file instead of copying and pasting?

2. We have faced issues with PNG transparency support in Photoshop. Have you faced similar issues? We are unable to do simple things like copying and pasting a transparent PNG in and out of Photoshop, and we're unsure if this is a bug, a feature, or we're doing something wrong. Actually, it performs copy-paste but loses the entire alpha channel.

Thanks in advance for your feedback!

1. I'm not aware of any image size limits in Photoshop although such limits may exist. It's more a matter of the capacity of the computer one is using.

2. I think dealing with PNG file variations is not unlike what one runs into with EPS vector files. If a file is created or modified outside of Adobe applications, it may not work properly when used later. I have experienced failures with EPS on a couple of occasions where the same application could not successfully open its own EPS exported file. CorelDRAW is one such application. But just copying and pasting an online image from one location to another, often results in the alpha channel being black. Usually this shortcoming is corrected by saving the image and then opening it in the second location or application instead of copying and pasting it. In the attached image, the top black box was copied and pasted into Photoshop while the same image below it was saved and placed in Photoshop.

The one issue I have seen with Photoshop and transparency is edge discolorization when an image is resized up or down. This is easily corrected by duplicating the layer in Photoshop and then merging the two layers. I have been told that the discolorization is less when the size change is in an even increment like 50% or 25% of original size.

Thanks everyone for your input - I forwarded it to the developer.