Hi @marial16 ,
Have you taken a try with the app's configuration I provided above?
Based on the error message screenshot that you mentioned, I think there is something with the File content passed from your canvas app to your flow.
I guess you passed the File Content to your flow using the following formula directly, right?
UploadedImage1.Image
the above formula would return blob data as below:
appres://blobmanager/4d007470709b4ec98e84e28de1ba58e4/1
which is not an binary data, it is just a reference to the memory in your device.
Within your flow, if you want to create a file in your SP Library, you must provide a binary data for this file. So within your canvas app, you must convert above blob data (e.g. appres://blobmanager/......) into a binary data firstly.
You could use the JSON function to convert your blob data into a base64 encoded data, then pass the converted base64 encoded data back to your flow.
'Your Flow Name'.Run(
AddMediaButton1.FileName, // Retrieve Uploaded File Name
Substitute(JSON(UploadedImage1.Image, JSONFormat.IncludeBinaryData),"""", "") // Get the binary data of the uploaded file
)
Please consider take a try with the app's configuration I provided above, then try it again, check if the issue is solved.
Of course, if you want to save the uploaded files into a collection, then pass the whole collection data back to your flow, you should also store binary data for the uploaded file in your collection rather than Blob data.
Please set the OnChange property of the AddMediaButton1 to following:
Collect(
FilesCollection,
{
FileName: AddMediaButton1.FileName,
FileContent: Substitute(JSON(UploadedImage1.Image, JSONFormat.IncludeBinaryData),"""", "")
}
)
after you attach a file through the "Add Picture" control, the file name and corresponding base64 encoded file content would be stored into this collection:

Then when you want to pass the whole collection to your flow, you need execute the following formula:
'FlowName'.Run(JSON(FilesCollection, JSONFormat.IncludeBinaryData))
After that, within your flow, you could use the dataUriToBinary() function to convert the passed base64 encoded data into a actual binary data. Based on the converted binary data, you could create file in your SP Library.
Best regards,