There are still screenshot uploads in progress. Apple App Submission

I encountered the same issue. The solution is to be patient. This is what i did: Upload screenshots one by one, after you upload each screenshot just refresh the page. And after upload if you see the screenshot is processing, remove it and upload again and refresh the page. Repeat the procedure till all your screenshots are up. Make sure you use Safari.

The most useful method is not to wait, but to constantly re-upload the waiting pictures

I compressed my images using compressjpeg.com. Now they uploaded fine.

I'm also facing the same issue, I just delete all my screenshot from every device and upload again and then getting the same issue, then after waiting a whole day, the next day I checked my images were uploaded.

It would appear that a Server side issue. While they fix it, we may need to trust that all photos will be prepared: on the off chance that you revive like clockwork, you will see that a few pictures that were gray with a cloud symbol are currently handled. I attempted and it would seem that it is a poorly conceived notion to attempt to supplant them once more. They all become dim once more. So how about we simply stand by until they are totally handled, while they work on the issue.

Useful link: https://developer.apple.com/forums/thread/649241

check my post: Error: There are still screenshot uploads in progress. On Apple App Submission

I also encountered the same issue (at least a similar symptom): I uploaded screenshots for the 6.5 & 5.5 displays and other displays also, but when I click the "Submit for review" button, it gave me the same error as above.

In my case, the solution is:
> DO NOT use JPG, simply convert the screenshots to PNG and upload, then the issue is gone. (E.G.: I was using Mac Preview app to convert/export the JPG files to PNG)

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By the way, the preview is not mandatory, I didn't upload the preview video but still, I can submit it successfully.

Our problem was uploading wrong size to Apple, e.g.: for 6.5 we uploaded the 5.5 images and vice-versa. Once we uploaded the proper images we need to wait for about 5 minutes and Apple allowed us to submit the app

Workaround FINALLY!

1. Go to "Product Page Optimization" tab
2. Click in the plus sign to "Create Product Page Test"
3. Fields: 3.1 Reference Name: Test 3.2 Number of Treatments: 1 3.3 Traffic Proportion: 50%
4. Click in "Create test"
5. Upload your images inside the "Treatment A" area
6. Click in "start test" and send it to review and await apple
7. Once this review was accepted, you gonna be able to apply the new images to your current published and/or published version.
8. Send you new app version to app review, like usual.

I encountered the same issue - tried to delete and upload again all screenshots several times, but nothing helped.

The reason was that we have several localizations but use screenshots only for primary language. But the broken screenshot was accidentally added to secondary language and was not visible at the first glance))

Found understanding for that issue here

"There are still screenshot uploads in progress." when submit a new build

Apple seems to have solved the problem.

The images that were in the upload process yesterday, this morning were already uploaded and I've been able to send my application for review.