Wallpapers don't have the exact same size in the window

[JeysonFlores]

Problem

Wallpapers don't have the same size on the window, so when a big wallpaper is loaded into the image view, the window resizes to allocate the image.

Reason

Gdk.Pixbuf sucks.

Solution ideas

Create a custom widget that draws the image using Cairo and uses it to draw a static size container for the images to show. (This principle could be used in a future version to show different wallpapers in the view as @lukors proposed in #3 .