GIMP, Krita, Darktable, and Inkscape are not made specifically for elementary OS or created with the HIG of elementary OS in mind, but they will get the job done and are available in AppCenter.
elementary OS has it's own photo manager called Photos which also allows for very basic picture manipulation tasks.
GIMP with Separate+
GIMP is a well known image manipulation program and a popular alternative to Photoshop. Although it doesn't have built-in CMYK support, the Separate+ plugin can allow you to convert from RGB to CMYK.
To install GIMP, head to AppCenter. A newer version can also be installed from Flathub.
This is not necessarily a complete solution for CMYK,...
I use Krita. It's a digital painting and illustration application. Krita offers CMYK support, HDR painting, perspective grids, dockers, filters, painting assistants, and many other features.
To install Krita, head to AppCenter. A newer version can also be installed from Flathub.
The closest I have found is montage from image magik. It's not quite what you want, and you may have already seen it and decided it won't work.
First, install imagemagik:
sudo apt-get install imagemagick
then we will use the montage command:
montage *.jpg -tile 5x -geometry 200x+10+0 montage.jpg
and it gives an output like this:
Click for a bigger ...
On elementary OS Loki 0.4, I solved the problem by installing dconf-editor
sudo apt-get install dconf-editor
Then with dconf-editor navigate to org/panthenon/photos/crop-settings and set last-crop-height, last-crop-menu-choice and last-crop-height values to 0.
Please note it should be exactly zero otherwise it will not work!
Thanks to @magicalex over on Ask Ubuntu, I have found something pretty close to what I was looking for. Sometimes it can crop the images slightly but you can click regenerate to try another arrangement. You can also swap images around by clicking them.
You can download it here
Well... You cannot really run professional CAD and Adobe applications on Linux.
You should either use a Mac or if you want to use Linux you should be prepared for some work. There are various options:
There is Wine & PlayOnLinux that add a Windows compatibility layer to Linux but first you need to check how these applications run on Linux at the ...
The problem with elementary is that all adobe and other design programs are not on Linux. So as far as I know, your best choice would be a Mac, as it is beautiful and has compatibility with all those programs.