Posting images to Shopify

Hey people in the Retool Community!

I am trying to connect my Retool app to Shopify, and post products from my app to Shopify using Shopify's REST API (Documentation can be found here).
POSTing the products is working fine, but I also want to post images connected to the products. This is where the trouble started. (PS: I am not very experienced using API, so this might be obvious :pleading_face:).

I thought that for the image source I can use the image URL fetched from the Retool storage. However, this doesn't work (I have made the picture public in the Retool Storage). Do you guys have any idea why it isn't working? It is something else I have to do in order to make sure the image can be found at the URL?

I am appending a screenshot of the message when I try to post the image using the "Create new product" endpoint.

image
image

I have also tried to post using the "Create new product image" endpoint (Link here). Then I get this error message:

I have tried to switch out the Retool Storage URL with this "dummy" Image URL (https://via.placeholder.com/150), and then both the methods are posting the picture as expected, which makes me believe it is something wrong with the URL from the Retool Storage.

Do anybody know what I am doing wrong?