Windows Phone 7.8 tile sizes - windows-phone

Question

I'm a bit confused. I got the 7.8 update yesterday and since the tiles are bigger now, do I need to update my app? As it is now the tiles looks a bit fuzzy and aren't as sharp as before.
According to the emulator the new tiles are 210 x 210 px.

Answer 1

You don't need to update your tiles because, as you noticed, the OS will scale the image to meet the new size requirement. This scaling can be up or down, actually, depending on whether it's for a small or medium sized tile.
Unfortunately, there is another complication: the new tile sizes are dependent on the resolution of the device screen. The medium sized tile is 210x210px for WVGA (which will cover all WP7.8 phones), but phones running 720p or WXGA (and remember that all apps that target WP7.8 can also run on WP8) have a medium sized tile of 336x336px. You can get a full listing of all tile sizes for all resolutions here: Windows Phone 8 Startscreen Tile sizes and margins.
You can discover the current resolution of the device using the following helper method (taken from this MSDN page).
public enum Resolutions { WVGA, WXGA, HD720p };
public static class ResolutionHelper
{
private static bool IsWvga
{
get
{
return App.Current.Host.Content.ScaleFactor == 100;
}
}
private static bool IsWxga
{
get
{
return App.Current.Host.Content.ScaleFactor == 160;
}
}
private static bool Is720p
{
get
{
return App.Current.Host.Content.ScaleFactor == 150;
}
}
public static Resolutions CurrentResolution
{
get
{
if (IsWvga) return Resolutions.WVGA;
else if (IsWxga) return Resolutions.WXGA;
else if (Is720p) return Resolutions.HD720p;
else throw new InvalidOperationException("Unknown resolution");
}
}
}