Why are my pictures on my fun advice profile blurry?

Can someone please tell me, why there are some pictures that you upload, for your profile pictures, on this site, come out so blurry, when they look clear, when you first upload them, and some are clear. Is there any way, to upload, so the pictures do not come out blurry, or to fix that, or is that just the way they come out, on certain pictures?

Maybe your original images are small and low quality. I suspect they may have been taken on a mobile phone.

When they are enlarged on your profile, they lose sharpness and quality.

Its just because of the size difference. If you want to look at the clear, original size; right click the image and go to "view image".