Feature request: Update last-modified time of existing files

[Flandyn]

I have downloaded a lot of images from Flickr (over 1TB) before there was an update which added the last-modified time to downloaded files.
If I was to redownload everything it would take too much time.
Is it possible to simply update the last modified time of existing files?

[mikf]

I'm not entirely sure using the Last-Modified times for "older" Flickr images is such a good idea. Take for example this image:

https://live.staticflickr.com/7463/16089302239_de18cd8017_b.jpg

It's Last-Modified header says Fri, 01 Mar 2019 14:33:50 GMT, even though it was uploaded in 2015.

Anyway, 16c582a adds an mtime post-processor and a --mtime-from-date command-line switch that can set modification times according to a file's metadata. In combination with --no-download from 6209728, you can update your files' mtime with:

$ gallery-dl --no-download --mtime-from-date -o skip=false <Flickr URL>

If you really want Last-Modified times, I can implement this as well, but, as I said, it might not be as useful as the actual upload date.