Couple of questions and an issue with form builder.....

1. What is the best way to have tax automatically added to the total? My form currently has a multiplier payment for people to order mugs and I cannot just put the tax amount in per mug because they may choose more than 1

2. I have a form setup right now at http://storksnmore.net/printing/mothers_day_mug_order.php and I wanted City, State Zip to all be on the same line. In the form builder program it all looks fine. (attached a screen shot) I have the form set to 100% width and item width to 100%. I have the field for City set to 50% and the City and State to 20% each but when in the browser the input fields appear larger.

3. I have chosen to allow for an upload of an image. I set the max size to 8192kb (max allowed by FB) - if my calculations are correct that should equal 8mb. I went to test the form and attempted to upload a photo that was 6mb in size and it told me it exceeded the maximum amount that the form will allow when i tried to submit it. I tried again with a photo that is 3mb and the same thing happened. The third time I tried it I used a photo that was 1.8MB and that was the only time it allowed a photo to be uploaded.