Rejected image

And then this image (attached) which is very similar in quality has been rejected due to quality issues.

By @Melisa Dupre

No, the assets are not very similar. The point of interest is missing to the rejected one. So that makes of the rejected picture a door in focus and the main subject out of focus. The other way around (also in both cases), it could have worked out because the radiation sign is even recognizable when blurred out.

Consider taking some photography courses to improve your technique.

• Select 5-10 of your very best images and compare them with current Stock inventory. 
• Is yours better than what Stock has?  Is it special in some way that separates it from all the rest? 
• As a customer, would you buy it?  What would you use it for?
• If you answered "no" or "I don't know," don't submit it to Stock.

With your remaining images, examine them at 100-300% magnification in Photoshop and correct all image flaws.  If you can't fix it, discard it and move on to the next one.  Repeat this process.

That should help reduce your rejection rate.

Firsts of all, it is the same image with just the sign removed. That will get your account suspended for spamming if you are not carefull.

To answer your question. The attached image has no subject in focus. The wall is not a subject. It is the foreground and not important. The xray sign is a subject.