"Not a valid PNG file" error prevents me from uploading.

[Engineer_Tf2]

It says it's "Not a valid PNG file" as seen in the screenshot below. I'm not sure why this prevents it from uploading? Any help would be appreciated.

 

[Manko-sensei]

Have you checked the size of that single page doesn't exceed the maximum parameters for images? Have you removed it and added it again or refreshed the whole page to make sure the issue doesn't persist? Those are the only questions I came up with that screenshot.

 

[RogueKitsune]

Chances are they are corrupted in some way. I know there are (or were) certain settings that you could set in Photoshop that would generate bad PNGs when exporting.

You could try running then through something like pingo or imagemagick to strip out metadata and colour profiles, as that's where the issue likely is.

 

[Engineer_Tf2]

Chances are they are corrupted in some way. I know there are (or were) certain settings that you could set in Photoshop that would generate bad PNGs when exporting.

You could try running then through something like pingo or imagemagick to strip out metadata and colour profiles, as that's where the issue likely is.

I found something similar. I use Gimp 2.10 for my program, and it for some reason didn't like that it would save data for the thumbnail, so I disabled saving thumbnail data and it works now!

 

[HDMI1]

I had this happen before when .webp files were only extension renamed to .png. I had to run them through a converter to fix them. You can use Irfanview or a "Save as PNG" extension in your browser; I think Windows has a free one you can download from the Microsoft store as well.

 

[MrIncognito]

I had this happen before when .webp files were only extension renamed to .png. I had to run them through a converter to fix them. You can use Irfanview or a "Save as PNG" extension in your browser; I think Windows has a free one you can download from the Microsoft store as well.

A tip for everyone reading this: just changing the file extension of a file does not convert it, it just changes the name. Changing the extension in the "save as" dialog of a program has behavior that is different depending on the program. Make sure you know what you're doing when manually changing file extensions.