Problems with resolution when uploading

Welcome to Adobe stock!

Everything is fine. The quality of the pictures you uploaded is as the upload file. There are no transformations done. People buying your pictures will get EXACTLY the quality you used to compress the JPEG file. Your second image is only a size reduced thumbnail from your portfolio at https://contributor.stock.adobe.com. It's OK for previewing. That's all.

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

I don't know what the second picture is. It's a tiny, tiny picture 220 x 124 pixels. Since you CANNOT download full resolution images from stock (and can't buy your own), it's not clear what you are looking at, and how you get it.

It can't be that a picture is reduced as much as the 2nd one. On Adobe stock, even the preview of this picture is larger. The original file has 8462 x 4760 px.