Good to know you, friend :)
I'm glad you brought this up because it actually ties in to something on my to-do list for Dreamchan this year.
I'd like to have a panel of client side, user configured settings, so that you can have your own preferences for things. Auto gif would definitely be one of those items, as those who don't want to download anything more than the thumbnail initially should be able to keep that option.
I had a few ideas for other items for the settings page, but if you have any more, feel free to leave them here. Thanks!