1) Open Photoshop； first;

2) Select "Image" in the menu bar, and then select the "Image Size" command. Open a dialogue window;

3) Set parameters, change the problem of image clarity in the column of "Resolution", and set the image size in height and width; As shown in the figure below:

Tip: Using ps software can easily change the resolution of files. When saving, you must change it to a picture format, such as jpg format. Cannot save in psd format, otherwise the file will be unrecognizable.