Hi, most of my images of this kind were rejected, because of quality issues

[sinedartx]

Sometimes I feel like its just because of very narrow focus. Or is the image too noisy?

[sinedartx]

These were also rejected.

[RALPH_L · Accepted solution]

The first photo: I do not think it is too noisy but, I do feel that there is not enough in focus.

Also, it is monochrome and I am not sure if there is a commercial value for all three of the photos.

[Jill_C · Accepted solution]

I can't detect anything in focus, and it's a monochrome conversion which is not permitted. How did you envision a Buyer using this image in a design?

[Abambo]

For sure, the focus is a problem. But you also have the issue that you did not read the requirements. BW pictures are rarely accepted. It is easy to convert a colour picture to bw but doing the inverse is impossible. But you also need to correctly expose your pictures. Last but not least, they need to have commercial value. 

If you are new to stock, you should consider these resources: https://helpx.adobe.com/stock/contributor/tutorials.html
Please read the contributor user manual for more information on Adobe stock contributions: https://helpx.adobe.com/stock/contributor/user-guide.html
See here for rejection reasons: https://helpx.adobe.com/stock/contributor/help/reasons-for-content-rejection.html
and especially quality and technical issues: https://helpx.adobe.com/stock/contributor/help/quality-and-technical-issues.html