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Your LimeSurvey version: [see right hand bottom of your LimeSurvey admin screen]
Own server or LimeSurvey hosting: Version 3.25.18
Survey theme/template:
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Hi,
I am looking for help because I don't succeed to upload a picture in a question group:

When I select a picture, I have a red cross (see attachment).

I can see that the picture appears in the source code, but not in the survey...

Thank you for the help,
Jessica

The red cross indicates that the image is inaccessible. Check that theimage is actually on the server, the path to the image is correct and the image directory has the correct permissions applied.