Created attachment 49620 [details]
Illustration #1

As you can see on this image, I've been trying to print a picture on a
100x150mm card (the cards you can buy in big chunks to print pictures suitable
for putting in picture frames. You can see that I made a CUSTOM papersize with
the values 100x150mm which is one of a couple of standard sizes existing.

Created attachment 49621 [details]
Illustration #2

After pressing 'printing' I am prompted with the GNOME printerUI and I felt
quite irritated once I get DIN A4 shown. I thought I made some customized paper
format within GThumb. Now what's going on ? Am I printing on a A4 paper or on a
100x150mm customized card format paper ready made for my picture frame ? And
where is the origin of that paper ? Bottom Left ? Top Right ? How do I put it
in my printer so it get's printed correctly ? From that image and from the
slots of my printer I must put the paper TOP RIGHT in the printer (there is
even an extra adaptor that takes such papers) but from your preview (because of
DIN A4) I must put it BOTTOM LEFT ? I am confused.

Created attachment 49622 [details]
Illustration #3

Print preview once shown doing the steps 1 & 2 (Illustration 1 & 2)

Created attachment 49623 [details]
Illustration #4

Strange thing is after I am redoing steps 1 & 2 again with the same instance of
GThumb and the same shown A4 paper in the GNOME printerUI dialog I will get a
small print preview image. But still I am not sure how to put the paper in the
printer to print this image correctly ?

I am also a bit irritated what scale 100% means 100% of what ? How figure I out
if I want 80x120mm instead of 100x150mm picture printed ? Why can't I rotate
the image on the paper so it comes out the way I want. There is a landscape and
portreit mode but this is not really giving the hit.

Paolo, are you actually reading bugreports for GThumb or giving at least some
feedback so we know that we didn't waste our time in filing stuff ?

>But still I am not sure how to put the paper in the printer to print this image
correctly ?

I guess a simple arrow as in the gimp print dialog can fix this.

>I am also a bit irritated what scale 100% means 100% of what ?

100% of the available space.

>How figure I out if I want 80x120mm instead of 100x150mm picture printed ?

you can change the paper size to 80x120

>Why can't I rotate the image on the paper so it comes out the way I want.

you can click on the image to rotate it

Maybe adding a tooltips that lets the user know that it's possible to rotate
would be a nice addition.

there is already a note in the dialog, no need for a tooltip.