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Problem reading excel/ reading image/movie files

URL of experiment:

Description of the problem:


I’ve been having problems running my experiments online. They work perfectly offline but will not work online. The problem is in loading the stimuli (images, movies) when the files are specified in a conditions excel. To try and figure out the issue I made a more basic version which is linked above. But I can’t seem to get even this basic task working. When the stimuli is specified as constant e.g. red.png, the experiment runs. But when specified in the exact same way but using a ‘conditions’ excel sheet and $variable, it does not work. I get the error message
"Unfortunately we encountered the following error:

  • when setting the image of ImageStim: image_2
  • the argument: red.jpg is not an image" }

Try to run the experiment again. If the error persists, contact the experiment designer."

In another version it doesn’t give any error message but does not present the stimuli.

Does anyone have any idea what I’m doing wrong?


Dear Louise

such error-message examplifies the different capabilities of PsychoPy and PsychoJS. PsychoPy is very good in finding the proper file and the file-format while PsychoJS is less capable or more restricted. The error message tells you that PsychoJS can recognize red.jpg as a proper image file. There might be various reasons: file-format and file-extension do not agree, an error in the stimulus-file aso. You need to proved access to your experiment or a toy-example (including conflicting stimuli, psyexp-file, stimulus-file) to get more help.

Best wishes Jens

Thanks Jens.

I’ve just changed the settings so hopefully you can now access the example project containing the issues I’m facing.

I’d really appreciate any help.

Have you added the resources you need via Experiment Settings / Online?


no access sofar. That is the error message I recieve when using the link posted above. No information available for this experiment: it may not exist or you may not have access to it.

Best wishes Jens

@wakecarter I have been uploading the whole project using the “sync with web” button on the GUI. All of the files appear to be there on gitlab.

@JensBoelte I tried to give access by changing the visibility settings through gitlab - maybe thats not the right way to do it?

I’ve been trying different things all day and at the moment it seems like the problem doesn’t happen until I specify rows in my loop. I specify rows like: 0,1,2,3
This works as desired offline but I get the error about the file not being an image when I put it online.


So it seems like entering the rows as 0:3 etc fixes the problem!
So strange!

Thanks for your help

Note that 0:3 is rows 0, 1 and 2 but not 3.

To get a single row you need for example, 3:4 for row 3.

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Thanks @wakecarter !