OS: Windows 10 64bit
Loading a PCX file generated by SpeedSys (PC benchmark for DOS) results in the image being stretched vertically in both the viewer and the browser.
Effect: Image displayed with an incorrect aspect ratio.
To reproduce:
1. Extract the attached ZIP file (SSTIMG01.zip)
2. Open the contained PCX file (SSTIMG01.PCX) in the viewer (or browser)
Actual behaviour (bug): Image displayed with an incorrect aspect ratio (see xnviw.png)

Expected behaviour: Image displayed with the original 4:3 (1.33) aspect ratio (see irfanview.png).
Note: I have the "Pixel ratio" option set to "Square" (default), which should maintain the original aspect ratio if I understand things correctly. The status bar area shows the correct information: "640x480x4 (1.33)". Pictures in other formats are displayed with their original (correct) aspect ratios.