images not approved due to quality issues

Stock images have to be highest quality & immediately recognizable to buyers.  If someone asks, "what is this?" you're not communicating the message well enough.  Nobody will buy it.

Compare your best work with current Stock inventory. If yours isn't as good or better than what Stock has, don't submit. There's a high chance it will be rejected. Read these links for more tips.

• https://helpx.adobe.com/stock/contributor/help/reasons-for-content-rejection.html
• https://helpx.adobe.com/stock/contributor/help/quality-and-technical-issues.html
• https://helpx.adobe.com/stock/contributor/user-guide.html/stock/contributor/help/photography-illustrations.ug.html
• https://helpx.adobe.com/stock/how-to/tips-stock-image-acceptance.html

Hope that helps.  Good luck.

The first is so underexposed, particularly in the shadows, that it's difficiult to discern what we're looking at...

In the second image, the eye goes automatically to the brightest area of the image, which is not the main subject. The animal needs to be considerably lighter - and in focus, of course.

In the third image, it looks like you've cranked up the saturation considerably; nevertheless, the animals need to be properly exposed and in focus. You would have to edit the foreground separately from the sky to retain the best elements of both parts of the scene.

First out of focus, second out of focus an probably badly exposed, and third may be also out of focus, but is surely underexposed and the DOF is too narrow.

In image #2, the animal needs to be brightened up. He's almost camoflauged, especially when competing against the burned out highlights where my attention was first drawn. In fact, if you have Photoshop, you might be able to use Gen Fill to remove the foreground object completely. 

The first image is too dark over all and possibly not marketable. 

Third image. Again, too dark, slanted horizon line, and the background antelope(?) are out of focus or were moving, causing motion blur.