Me gustaria saber las razones técnicas para rechazar estas fotos, para aprender

We can't tell much from small, low-resolution thumbnails.  There is insufficient detail and pixel data for us to evaluate.  You need to show us the full size images.

In the meantime, read these links.

• 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

These images are also too small to examine properly; but it is obvious that they are underexposed and over-saturated. If you would like more precise feedback, please post full size images.