Graphics can look different for any number of reasons, but as you say, you have solved that one !
Your profile photo :- Click on your name in the very top right of the BC screen and choose 'Profile'. When it opens you will see that fetching silhouette in the top left corner of your profile - I think it looks just like you - and either click on it or hover over it and a 'Change' button will appear. Click change and the upload dialogue box appears.
Before you get this far, make sure that the image you want to use is as you would like it to appear, either cropped down to head and shoulders or a graphic that has taken your fancy or you have sweated blood over, and as for size, a mininum of 200 pixcels is recommended. then you have two choices -
If the image is on your hard drive, use 'Browse', browse to the image then click 'Done'. If the image is on say Dropbox, then enter the URL of the image in the URL box and click 'Import'. Once your file is uploaded you have a chance to edit it somewhat before you present it to the world.
I look forward to seeing if your image is even more fetching than your silhouette ! Send me a PM, that will have your profile image in it as well.