/ask about quality of my picture and how to check my work before upload (the best way)

Regarding the 1st image on the left:
There is no focal point… just underbrush and such. 

Consider your audience:
What are they going to use the image for?
Who would need the image you are about to upload? People like a finished clean product.
Where would this image be use? A well manicured park… people would like to see. Leave space for copy or other assets to be placed.

Cheers

Nate

Does your camera have a built-in light meter? If not, you might want to consider getting a hand-held one. Or download an app for your smartphone. 

Proper light exposure should be fairly evenly distributed. If there’s not enough environmental light, consider using external light sources. 

https://photographylife.com/understanding-histograms-in-photography

It is tough to get accepted on platforms like Adobe Stock because the market is very crowded. Before you head out for a shoot you should search the database for your topic first. If there are already thousands of similar images you will struggle to get traction.

Try to find a unique angle or a different perspective that is currently missing. Focus on technical quality above all else. If your images have noise or lack sharpness they will likely be rejected. It is usually better to spend your time creating one high quality image than ten mediocre ones. If you do not focus on quality it will just be a waste of your time.

The image is too small to critique. Upload a couple of full-sized images here as they were originally submitted. The file size limit on the forum is 5MB, so it’s possible you may have to reduce the image somewhat, but keep it as large as possible within the 5MB limit. What I can say about the small version you linked to is that I see so central subject of note and the shadows appear underexposed.