How to check the file size of your photo
Open Windows explorer and locate your photo file (in the example below the photo file was in C:\Documents and Settings\All Users\Documents\My Pictures\Sample Pictures.)
At this point the size of the file may already be displayed, as in the screen shot below.
If the size is not shown, hover over the file name and right click on the file (using the Right hand side button on the mouse).
Click on properties and under the general tab you will see the size of your file.
If your file is too big; resize your photo and reduce the file size using an online cropping tool such as Photo Resizer