Low Quality In Vertical Pictures In Photoshop?

When I upload a picture to photoshop especially vertical pictures they come out with bad quality! Why is that happening? Any suggestions? I Use Nikon D5100.

What settings are you using on your camera? That's what will determine the quality of the picture. You should be using the best settings: highest quality and largest file. If you are taking pictures at a low setting then the images will be poor quality. A common mistake people make is to worry about how many images they can get on a memory card. Do not do this-always use the highest quality settings possible for your camera.

What exactly do you mean by 'bad quality'? I hope you're not comparing the image in Photoshop to how it looks on the camera. The latter can give misleading results, unless you're looking at the histogram.

Are you looking at the images at 100% zoom (Ctrl+1)? Don't make quality judgments at any other zoom level.

What camera settings are you using? Lens?