Hi Glenys
I am not sure why your images would appear darker once posted to the web site, if both the processing and the subsequent web viewing are viewed on the same monitor. If you are viewing on different devices, the problem could be due to the different brightness of devices, or the different types and brands of screens. However, there may be some technical information someone else can impart.
To answer your question, it is possible for a member to delete an image they have posted. Just go to Photo Gallery, My Photos, select the photo and hit Delete. However, this will remove everything. If you use the Edit function you can edit information attached to the photo but not the photo itself. I am not aware of any way to delete just the picture but leave all the other text entered (eg comments, camera information etc).
Perhaps the way to do it is to use the Edit button in My Photos, then cut and paste important text such as any Comments entered into a separate document. Then delete the file, and upload the new image as a New Image, cutting and pasting the text back into each field. The new image will need to be re-moderated.
A couple of useful things to check: 1) the histogram provides useful information on the brightness of the image which is not monitor dependent, so always check this; 2) Always assess the final image that you intend to submit to BLP as a final JPEG at the size you will submit it, don't rely solely on what the raw processor software shows; 3) if you can, check the calibration of any monitors you use; and 4) for difficult files it can be useful to check the final JPEG file on another screen. I find my iPad to be useful for this. iPad screens can be reasonably colour accurate, and the latest devices also have a neat trick where they can adjust their colour profile (as well as brightness) to compensate for the ambient light - in a sense calibrating themselves continuously.
Regards
Simon Pelling
BLP