Don’t modify spreadsheet variables
If you have a situation where you sometimes use the value of a variable from a spreadsheet in a component and sometimes want to change the value, copy the value to a different variable. Editing the spreadsheet variable causes an error online.
Locally, something like this will work:
if imageFile == 'x': # where imageFile comes from a spreadsheet
imageFile = 'transparent.png'
To ensure online compatibility, do this instead:
if imageFile == 'x': # where imageFile comes from a spreadsheet
thisImage = 'transparent.png'
else:
thisImage = imageFile
In this case, you should also put thisImage = 'transparent.png' in Begin Experiment