Update a wordpress blog/ online portfolio

I have a small job, I have three high resolution images that I am having difficulty uploading to my wordpress site. For some reason once I upload the pictures, the color looks very drab and gray-ish. I do not know how they should be formatted to look their best.

I have also recently changed my twitter handle, I have a plug-in that feeds my tweets to my blog, but I need that changed too.

Thank you!