I have also created The Mausoleum of halicanessus. Hope you enjoy it.
preview is inside when you download it.

Please see my comments in this thread:
http://forums.civfanatics.com/showthread.php?t=116263
since the same problems exist in these images.

Sorry, but I don't understand why you make the Mausoleum that is already in the game? The Mausoleum of Mausollos and the Mausoleum of Helikarnassos is exactly the same thing.

http://en.wikipedia.org/wiki/Mausoleum_of_Maussollos

Okay, some ideas. The picture you chose is nice, but you did not keep the aspect ratio when resizing (you reduced the width not in the same way as height). That doesn't look right. Look in your graphics program, whatever you use, for the option "Keep aspect ratio". The other thing is, the Bitmap that's in the file is useless. Maybe you should re-zip it without the *.bmp to save over 80kb file size.

Besides, Bjornlo gave a truckload of good hints.