You are almost certainly saving your photo in the Adobe RGB or ProPhoto RGB colour space. For web use, you need to save images in sRGB only (even if they look OK on other sites to you, they won't to many other people).
Hi Alexis
Thank you for this information, it may answer the problem I had with my first image that I eventually substitued for the raspberries and cream.
Thank you
Welcome to 365. This is a constant concern. Not only do I lose color tone on the upload
my pictures are blurry if I email instead of upload straight from my computer.
See here for a full discussion and some tips on how to adjust your workflow to use sRGB:
http://365project.org/discuss/general/13954/why-are-the-colors-less-vibrant-in-my-uploaded-photos
I substitued my first image because it was so dark also.
Patricia Griffin
Thank you for this information, it may answer the problem I had with my first image that I eventually substitued for the raspberries and cream.
Thank you
my pictures are blurry if I email instead of upload straight from my computer.