| Reference | Downloads | Github

Unable to download resource

I am new to online testing and am struggling to get anything to work on pavlovia as none of my images will load.

I created a super basic practice experiment which simply involves an image component appearing for 5 seconds. It works completely fine when run offline but when I click to Pilot it on pavlovia I get the error:

  • when downloading the resources for experiment: Image
  • unable to download resource: images/image1.PNG (FILE_LOAD_ERROR)

I have read so many posts on this forum trying to solve this, and none have worked.
There is only one small image, and I have tried with different file formats.
I have also added the file to the ‘additional files’ section of the settings>online tab.
Each time I sync I clear my cache
Lots of previous posts talk about the html/resources folder however more recent posts seem to suggest this is no longer a thing…and I dont have these folders.

Does anyone have any idea as to what could be causing this error?

Maybe try it out with a different image to see what happens then? For instance, I’m quite sure the PNG file in this experiment loads without errors.


I’m getting the same error at the moment. Works fine in Psychopy. Have checked the image files and uploads all seem fine and are in /png format. They the same images have worked fine for me on another online Pavlovia experiment, so in my case not an issue with the files. For me the error changes with the resource specified changing (e.g. sometimes img 5 sometimes img 6 etc) suggesting some sort of general loading error? Very appreciative of any suggestions. Clearing cache and running using incognito don’t fix the issue. Is it possible to have too many or too large image files? Or too many nested loops?

code here:

Hi, all!! I’d like to add that I’ve been experiencing the same thing as described in katDyke’s post above. Like katDyke, moreover, I have followed pretty nearly all threads on this & similar topics, & have tried all the fixes suggested that don’t involve hard-core coding, and I still have no resolution to the problem.

If anyone has any advice/ suggestions, they’re very welcome!! Thank you all!!! :slight_smile:

  • cLEE.

Oops! I forgot to include the link to my experiment (which I can only pilot at present, having no license.)


Thanks for your speedy reply!

I have tried it with your kitten picture but no luck.
When I run your e2e_img experiment through the Explore section of pavlovia it loads just fine, however when I put your kitten picture into my study it is unable to load it.

OK, let’s find out what’s up!

  • @cLEE, I can’t access your experiment, could you give me access? (or make it public)
  • @EJJ, could I also have access to yours?

Thank you - I am probably doing something stupid but it for the life of me I cant see what it is thats the problem!

Its public and in piloting mode

Hi @ thomas_pronk :-). I replied a short while ago by messaging you directly, sharing my login ID & pw. I’m not sure whether my message went through, & can’t seem to find a log of my ‘sent’ messages. I’d much appreciate it if you’d let me know if you received my message.

Thanks a tonne!

  • cLEE.

@EJJ, I cloned your experiment and I can tell you what’s going wrong. The file has it’s extension in lowercase (img_kitten_png.png), but in the image stimulus you refer to it with uppercase (img_kitten_png.PNG).

I assume that this worked locally because in Windows, filenames aren’t case-sensitive (i.e. Windows doesn’t care whether you write img_kitten_png.png or img_kitten_png.PNG). But on the Internet, this does matter.

By writing img_kitten_png.png instead, my version of your experiment did work online.


@cLEE, sent you a PM in reply

Yes, I just responded to that, thanks!


Oh my what a silly mistake for me not to have noticed!

Thank you so much for taking the time to look at this for me :slight_smile:


1 Like

@cLEE, to give others access to you experiment, take the following steps:

  • On, at the page for managing your experiment, click “View Code”
  • This will take you to the repo of your experiment, hosted on
  • At the left is a panel, with various links, one of them being “Settings”. Click Settings, then Members.
  • You’ll see a page where you can invite members to your repo, thus giving them access.
  • To be sure that the member has access to your experiment code, give a member the “developer” or “maintainer” role.

My username on pavlovia is tpronk.

Hope this helps!

@ thomas_pronk: Thank you very much indeed for that information. I have just added your ID, and am hopeful of resolving this soon, with your advice.


  • cLEE. :smiley:

Hey @cLEE, I think your issue has the same cause as @EJJ had. See my earlier post in this thread for a detailed reflection.

Applied to your experiment: I got an error message that referred to “Rita_008-Hop.png”, but the filename of this stimulus is “RITA_008-Hop.png”. Changing Rita to RITA wil probably fix the error.

@ thomas_pronk, You were right, thank you! :smiley: I had looked up a similar error in a thread posted previously, and had gone back and verified the “.png” vs. “.PNG” issue, but had missed the big, white elephant on the sofa – the case mismatch in my filenames!! 8-< Thanks, awfully… but for your pointing that out, I’d probably still be looking for the proverbial nose on my face.

  • cLEE.
1 Like

I’ll leave this here in case it helps anyone - I found my issue and it’s one of those annoying careless ones…
Psychopy didn’t care about case sensitivity in image file names in .csv file and so it ran fine, but…Pavlovia did and so wouldn’t load them. So if you’ve done everything else check case sensitivity very carefully!

1 Like