How do you make the images in the Poll larger and how do you remove the black background?
are you referring to our photo contest feature?
Could you explain a bit more what the problem is?
We generate a thumbnail for each photo. If you click a photo the lightbox will open with a big view of the image. In the ligthbox you can switch to fullscreen mode by clicking the icon or using the shortcut "F". You can also toggle the voting controls in the lightbox context menu (three dots in the lower right corner) or with the shortcut "Shift + F".
We fill the background with black when the photo does not fit your screen. Do you think another color is better?
We've added some new customisations options which may help.
You can now change layout options of photo contests. This includes an image cover mode which would remove the black background of images in the gallery.
Further more you can create custom style sheets to change the default appearance.
Read more in our blog post »Customizations for individual polls and photo contests«.