Simulate Calibre recipe with browser?
I've got a recipe that works, but it pulls an image that is slightly different from the image I see when I go to the page the image came from. The log shows that the recipe is actually fetching the image I want, but Calibre doesn't get that image. It gets one similar, but different. When I use a browser to directly view the URL of the image that the recipe is fetching, I see the image I want, not the one that Calibre gets.
I've tried turning off cookies in the browser, clearing cookies, clearing the cache and fetching the image again, but I always get the image I want in the browser, and never get the image that Calibre's recipe gets. I've tried changing the useragent string, blocking the referrer, etc., but I can't seem to simulate Calibre with the browser closely enough that I get the same image that Calibre gets.
What am I missing? How does the site know that a Calibre recipe is grabbing the image? Comments? Thanks.