Bill, 99% of the time if your pictures look different after you upload them to an online image host, it is the image host. However it never hurts to check your monitor and calibrate it as often as might be necessary because they do drift.


If you don't have something like a spider or the calibration charts here is a nice site for calibrating your display. >> Monitor Test Images





On Edit: Correction
Some of the differences are the image host, In addition to that it is also your web browser! When you're working with a Image editor it is either to software and/or your monitor that is rendering your image data to the screen. When you use a web browser it is the browser that is rendering the page.