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Your LimeSurvey version: [see right hand bottom of your LimeSurvey admin screen]
Own server or LimeSurvey hosting:
Survey theme/template:
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How exactly does the file system with added pictures work?  I figured out how to import a picture from a third-party cloud (Imgur) into the css file of the theme, but I would like to do everything directly. Can you suggest the correct line so that the picture uploaded to the topic could stand up, in my case, as the background of the survey?
That's how I did it now:
.simplex{background-image: url("[url] i.imgur.com/t2s5TWU.jpg%22 [/url]); }
.outerframe .container-md { background-image: url("[url] i.imgur.com/t2s5TWU.jpg%22 [/url]); }