Unreadable and mangled captcha with image widths > 270

[marcopaganini]

Hello,

Text only renders properly in images up to 270 pixels in width. Above this size, the amount of mangling will increase with the resolution, until text becomes unreadable.

Here's side-by-side view of the problem using CreateCustom with the string 5678 and different resolutions starting at width 240 to 380:

At larger resolutions, things become really "interesting". Here's an example using a width of 640 pixels: