[SUGGESTON] Consistent image size: KeepParameters improvement

[RndUsr123]

Cycling through different-sized pictures may lead to significant variations in displayed size, depending on settings. What if an extra mode were added to KeepParameters to prevent this from happening?

The preference should be split into:
KeepParameters: keeps pan, contrast, gamma, sharpen and rotation (but not zoom) consistent between images;
KeepSize: this is the actual suggestion, a preference which keeps all images similar in size using:

• Zoom - nothing new here
• Width - zoom is dynamically adjusted between images in order to prevent changes in displayed width
• Height - same as width but based on height
• Area - tries to maintain the same overall size, scaling zoom level based on the mean of width and height

Important note: each of these should be computed over the previous image to retain the approximate size set by manually zooming.
"Area" is really not the area, but I'd argue it looks better that way as the longest dimension is kept closer between images, never exceeding 2x