It's easy to use! I'm able to upload photos from my computer or phone (even if they're stored locally) without any problems at all.
The size limit for uploading pictures seems quite low - it may be possible that there are some files which will not go through but this has never been an issue with me so far. They do offer free accounts as well though these seem limited compared to their premium options by offering only 5 GB space per account instead of 10GB+. If you want quick access to your images then photbucket would suit perfectly; no matter where you store them beforehand, whether via internet storage services such as Google Drive/Dropbox etc., local device memory like phones & tablets or even external hard drives connected directly into computers using USB cables, just plug-and-play once inside photbucks website itself and start editing away :).