Remove allow_image_download parameter

[lukavdplas]

If a corpus has image attachments, you can set the parameter allow_image_download to control whether the frontend interface will show a download button next to the image. (No effect for PDF attachments.)

This is a bit of a misnomer; if the user is viewing the image they have already downloaded it, and they can always save it to more permanent location with right-click -> "Save as" or such. (Which is not like, an exploit, just the intended functionality of the browser.) So this parameter does not "allow" anything, it just adds some extra convenience.

I was going to suggest that allow_image_download should be True by default (it's not), but then I could not think of any use case where you would set this to False. If you wanted to prevent users saving images, this will not do that, but even if it would: why? It's not like we're selling subscriptions. And if the images are valuable research material (otherwise we would not include them), a researcher should be able to save them for future reference.

[jgonggrijp]

Could this have been a "best effort" concession to a greedy publisher?

[lukavdplas]

It's hard to tell since the parameter is never explicitly set to False. But it's also characteristic for early development on I-analyzer that things were locked up "just in case", so this may well have been on the lab's own initiative.

[jgonggrijp]

I somewhat recognize the "just in case" mentality of old, but this one seems rather non-technical for an initiative of our own. I would be surprised if anyone at the lab wasn't aware that you cannot prevent a browser from downloading images.