Better embed functionality

[ordinarygulp]

Right now, on many sites, bbcode images show the full image, instead of thumbnails. Perhaps setting a static thumbnail, instead of resizing the full image would be a good solution? For example: upon image upload, generate a 300x250 (maybe make the resolution user-changeable in their account settings) jpeg thumbnail, which links to full size image as it does now.

Right now, this line is generating a static size, that is too small: https://github.com/bhutanio/imagehost/blob/5da3ce5d59a83cafdf5f7ec99faf4e3d4fe4da09/app/Http/Controllers/Image/ViewImagesController.php#L75

EDIT: It seems thumbnails exist, but are only used for html embed. Maybe add that functionality to BBCode?

[ordinarygulp]

Temp fix in https://github.com/bhutanio/imagehost/pull/11