CTF images are stretched with K3 data

[JuhaHuiskonen]

CTF diagnostic images are stretched with K3 data (non-square micrographs)

To Reproduce
Steps to reproduce the behavior:

1. Run CTFfind4 for a rectangular micrograph, for which a thumbnail exists
2. Click Analyse results
3. The dimensions of the power spectrum (CTF diagnostic image) are not square when displayed next to the micrograph thumbnail (they are scaled to the same dimensions)

Expected behavior
The power spectrum image should be square