I've been having this issue since 2013 ( probably ) with FF 19, even with the official Echofon.
Every time I tried to send a tweet with an image attached ( triangle -> Add Image ) the tweet just vanishes but it won't appear in the timeline.
Of course, the image doesn't show up in the gallery either.
Sometime, after a lot of waiting, an error message appeared near the twwet composition box but I can't replicate it anymore.
Tweets sent from the twitter page don't have issues.
Tested with many official releases of FF up to 36.0.1 with a clean profile and no other plugin but echofon.
I've been having this issue since 2013 ( probably ) with FF 19, even with the official Echofon. Every time I tried to send a tweet with an image attached ( triangle -> Add Image ) the tweet just vanishes but it won't appear in the timeline. Of course, the image doesn't show up in the gallery either.
Sometime, after a lot of waiting, an error message appeared near the twwet composition box but I can't replicate it anymore. Tweets sent from the twitter page don't have issues.
Tested with many official releases of FF up to 36.0.1 with a clean profile and no other plugin but echofon.