If I submit image as exclusive to DT and later decide to sell it elsewhere would I be able to cancel it's exclusivity?
And vice versa situation: would I be able to make image exclusive once it's approved if I decide to stop selling it elsewhere?
If it's possible is there any grace period between changing status of images?

Thank you!

I have never tried the first situation, but I set two images as exclusive as they were selling nowhere but in DT (both illustrations).  I believe both ways are valid. 

Regards,
Adelaide

QuoteA Contributor may remove the exclusivity rights to an image with thirty (30) days prior written notice to Dreamstime.com.

that was from THIS PAGE near the bottom

For the second part of your question, yes you can make it exclusive anytime after it is approved so long as you are not selling it on other sites.  This is done by checking the box in the "online files" section of your management area.

thanks for clarification, folks!
I guess that I'd better upload images without exclusivity and if I fail or decide not to add them to other stocks I'll make them exclusive to DT.