Not a huge help since you need a dead image link before you can gain access and there's no way to browse or generate new links, but this could be useful for old posts that weren't uploaded at full resolution, so long as there's a dead link to convert. Anyway, here's how: You have your dead source link- http://data.tumblr.com/68d3bebbfe6e27120412b93f08b11041/tumblr_ov871tMLLa1vymad6o1_raw.png
Which brings up an XML error page. You replace 'data' with '78.media' and 'raw' with '1280': https://78.media.tumblr.com/68d3bebbfe6e27120412b93f08b11041/tumblr_ov871tMLLa1vymad6o1_1280.png
Boom, full-size image from a deactivated tumblr. I don't know if the files stay on tumblr's servers indefinitely or if they're deleted after a certain period, so give it a try on something older than a year and post your results here!

I want to point out this doesn't mean a Tumblr is deactivated, it's just because they closed the loophole that allowed access to the _raw files.

MagnusEffect said:
I want to point out this doesn't mean a Tumblr is deactivated, it's just because they closed the loophole that allowed access to the _raw files.

What about the uploaders themselves, do they have access to the raw links?

Munkelzahn said:
What about the uploaders themselves, do they have access to the raw links?

No.

Tumblr will keep image files forever and if you have direct link you can always access them. This is why it's good to have BOTH tumblr blog post AND direct URL in source field!

Reblogs also never go down even if source blog is nuked, so this is why all the information is good and services like google and wayback machine will help you get the image even if the blog isn't no more.

In OP example raw links in general stopped working so this is simply modifying the link back to sample version.

MagnusEffect said:
I want to point out this doesn't mean a Tumblr is deactivated, it's just because they closed the loophole that allowed access to the _raw files.

Ah, didn't know that, thanks! The ones I was working with were deleted/deactivated, so assumed a correlation.

Mairo said:
Tumblr will keep image files forever and if you have direct link you can always access them. This is why it's good to have BOTH tumblr blog post AND direct URL in source field!

Reblogs also never go down even if source blog is nuked, so this is why all the information is good and services like google and wayback machine will help you get the image even if the blog isn't no more.

In OP example raw links in general stopped working so this is simply modifying the link back to sample version.

Oh cool! That's good info, thank you! Yeah, I wish people included several links on everything. An automatic transferal of the URL to being source link when people upload from URL would help with some cases, no idea what percentage.