This link below is a pretty good explanation of how to setup hosting your images (or other files) using Google Drive. The same thing can be done with Dropbox or most other cloud storage. But just by having a Google account you already have 15GB on GD. You can put your company logo, Twitter and Facebook icons - whatever you need in a folder on GD.
I use hosting images for custom signatures for several phones, tablets and Windows and Linux desktops. The advantage is everything is always in the same place. If I do a reset, reinstall or get a new device no transfer of files is needed. So, for example with AquaMail, I just reload a backup and accounts, signatures, everything is as it was. (Well, almost. I've noticed AquaMail misses saving a couple of minor settings. The only bug I've found so far.) I do the same thing with Thunderbird on desktops. That's one reason why so much email you receive has remote hosted images rather than imbedded. Simplified setup after the initial install. The other main reason is to reduce the size of emails.
This link below is specific to Gmail, but don't let that spook you. It works the same for other email clients. Basically you just paste in the image location in GD to a dialog box in AquaMail instead of selecting an image file.
http://gappstips.com/gmail/use-google-drive-to-host-your-gmail-signature/
Android since v1.0. Linux user since 2001.