Where to upload to photo hosting from a phone or tablet?

Question

Mobile devices

Good day!
I have a forum where people often share their impressions of trips, post pictures.
To upload photos, I installed the free version of Chevereto 2.5.
But the trick is that it uses flash and for iPhones it turns out that it does not work.
Tell me, plz, what to recommend to people who want to upload their photos somewhere on the Internet from mobile devices and get a link to insert into the forum? It is desirable that it was still possible to resize photos to a given width.
Thank you!