Add support for downloading remote images

[designbymind]

Additional expectingImage param for extraParams object.

[Topener]

Hi! Thanks for your contribution, it looks like this can be used for any filetype, not just images. Perhaps change it to a more generic implementation? expectRaw for example?

[Topener]

Ok looking good! Could you bring in the changes in the recent update? Then I can go ahead and merge it!