By default when I open an image it fits to the window size (scale it down). I have to hit the button "Show the image at its normal size" every time when I go to the Next/Previous image or open a new image.
I tried this, but it doesn't work.
I think that it is probably just impossible. Image Viewer is pretty simple app generally. What I would recommend You is to install Gthumb, which has more functions, including the one You need.
sudo apt-get install gthumb
There You can find this option in Preferences and Viewer tab I guess.
I know that this isn't the exact answer You're looking for, but I hope that it will help anyway.
The only suggestion I can come up with is the qiv image viewer
I hope this helps
This just needs the maintainer of Eye of GNOME (eog) to create a plugins file for version 3.6.2.
There is one for 3.6.1, and copying it (with only a minor change) should solve this. Within the download file (.zip or .tar.gz) the file '/eog-plugins/config.ac' needs line 5 changed: from
[3.6.2]. The remaining code seems to all be >= 3.5.5 compatible.
This should be raised as a bug/feature ..