If your research is publicly funded then you may in fact be obliged to make all of your data available as terms of your grant. You must cite other people who have contributed to figures where necessary.
Most publishers (>90% including all major publishers) do not consider sharing your research outputs on online platforms as prior publication. F1000 did some research on this subject and the journal policies can be seen here.
Please be aware that publishing already published articles are not allowed as these already have a DOI assigned, please see figshare's policy.
If you are still unsure and wish to upload a version of the published paper or part of it, you should review the publisher’s copyright policies or get in contact with them.