Yeah, this isnīt really a Java question but it could also be due to the reason that if you have a "height" and/or "width" inside the <img> tag, it may distort the image if the ratio is different. Most browsers donīt handle scaling images down/up very well. My suggestion would be to change the images to the right size first and then bind them into the <img> tag without any size constraints and it will show perfectly.
If you need some software to change the images, try "irfan view" which is a really goo program to optimize images for the web.
I think, therefore I am....... I think.