IO Error — unable to upload pics

Tonight I am getting IO Error messages when I try to uploaded images to my self-hosted WordPress blog. I have uploaded images like these without trouble for the last two months. Can anyone tell me why it would suddenly stop working like this. I am using the uploaded in the Post and the error I receive is IO ERROR.

I researched the topic — many others have had similar problems, but there was disagreement in the forums about the answer —
perhaps it involves flash — perhaps it involves an SSL certificate — https versus http…. etc.????

THanks for any help.