My boss wanted to have a logo in the header of our website but since our logo didn't have the square 150x150 dimension I had to modify my child theme a little. I used the method suggested here which worked like a charm on the frontend. Btw, I changed my child theme via de WP Dashboard -> Appearance -> Editor.
But now I do have a little problem with my backend (dashboard). Whenever I change something (like change some code in the editor, or add a picture), the change will happen, but I will get a blank screen and cannot get back to the dashboard unless I open a new window and go there (I'm not being logged out or anything).
And the media library is also not accessible when I try to add a picture.
This all started to happen once I added the code for the logo in the child theme functions-file. Does anyone have a clue how this could be related? Thanks!