Photoshop reduces the quality of my image

[marousofr]

Hello everyone, 
So I made this image into a vector art effect in photoshop. The image is a high-quality one. Although the quality is very good when I save it, when I try to put it into photoshop it reduces the quality dramatically. 

I think it is important to mention that I try to put this image into a 1024 x 384 px document

Thank you 

[D Fosse]

Reduced quality how, exactly?

You're putting this into a very small file. 384 pixels high is almost thumbnail size and certainly not enough for any "high quality" image.

So if what you're seeing is loss of resolution and pixelation, that's expected. That's not Photoshop, just the image size.

[marousofr]

Yes. It losses resolution and it has high pixelation. So i have to reduce the image size to feet the thumbnail ?

[D Fosse]

As I said, that has nothing to do with Photoshop. That's because you are reducing the image size to only 384 pixels high. If that's the size you need or want, then that's what you get.