The download button opens the iTunes App Store, where you
may continue the download process. You must have iTunes installed with an
active iTunes account in order to download and install the software. This
download may not be available in some countries.
From Evgeniy Podsevalov:
Rescreen - compact smart utility for designers of iOS interfaces and icons, artists of mobile content, developers of iOS apps and all other who like to develop and paint.Just upload your images from web browser on desktop computer (icons or screen sketches) to mobile device. Rescreen automatically sort images and you can see them in original size.Attention! For best results, use the original image size, for example, the icon on the iPad with retina screen resolution should be 152152 px, and the screen image 2048x1536. In free version you can see only 4 icon and 4 screenshot.