Why Photoshop double my image size when I export it ?

[Blondiefromwood]

Hi everyone,

If I post this message it's because I already browse all the Internet and I'm totally crazy ! 
When I save an image (here 500x165px), the export file looks bigger and very bad quality.

I try all the export settings, from save menu, from "Save for the web". It's always the save trouble.

Do you know where it comes from ?

Thanks a lot for your help !!!

BTW I'm using the last Photoshop CC version (21.1). 

[davescm]

You image viewer is scaling the image , Photoshop is not.

At 100% zoom, Photoshop maps exactly 1 image pixel to 1 screen pixel. So the size on screen depends on the pixel density of the monitor. It does this for absolute pixel accuracy.

Other viewers/browsers scale the image so it displays larger on a high pixel density screen (e.g. retina screen). That scaling might for example map 1 image pixel onto 4 screen pixels which will look slightly blocky or use an in between scaling which will reduce sharpness at the edges.
In short - that is not a Photoshop issue, although you can simulate the scaling in Photoshop by viewing at 200% zoom.

Dave