gunzip downloaded images

[phette23]

Twitter's servers send some of the images as application/x-gzip files (e.g. see https://pbs.twimg.com/media/B0AsATdCEAAbbnP.jpg — after download, exiftool reports x-gzip as MIME Type). The files just need to be unzipped to be accessed but the best way to do that is up for debate:

• function that runs through the images dir unzipping each after the download stage (easy, but another stage, slow)
• try to stream responses through an unzip process (less easy, probably requires a new dependency)
• see if Twitter follows HTTP headers requesting uncompressed content (probably one line of code, trivially larger download)

I'm leaning toward an HTTP Accept: image/* header if it works.

[phette23]

Sending an Accept: image/* to Twitter doesn't seem to affect what they send in response. See the issue2 branch which includes a script (in "bin/gunzip-img.sh") that iterates over files in the images directory, gunzipping them.