convert recovery images to palettized PNGs

Cuts the byte size of the recovery images in half, roughly.

Change-Id: I453a499e9937163c545dab3c552201882766e218
diff --git a/res/images/icon_error.png b/res/images/icon_error.png
index 6cfcc8a..446c3fb 100644
--- a/res/images/icon_error.png
+++ b/res/images/icon_error.png
Binary files differ
diff --git a/res/images/icon_installing.png b/res/images/icon_installing.png
index 2866b04..7e42628 100644
--- a/res/images/icon_installing.png
+++ b/res/images/icon_installing.png
Binary files differ
diff --git a/res/images/icon_installing_overlay01.png b/res/images/icon_installing_overlay01.png
index c71d840..2c4c89a 100644
--- a/res/images/icon_installing_overlay01.png
+++ b/res/images/icon_installing_overlay01.png
Binary files differ
diff --git a/res/images/icon_installing_overlay02.png b/res/images/icon_installing_overlay02.png
index 4c97c78..b63552b 100644
--- a/res/images/icon_installing_overlay02.png
+++ b/res/images/icon_installing_overlay02.png
Binary files differ
diff --git a/res/images/icon_installing_overlay03.png b/res/images/icon_installing_overlay03.png
index ff4ee94..6acb5ef 100644
--- a/res/images/icon_installing_overlay03.png
+++ b/res/images/icon_installing_overlay03.png
Binary files differ
diff --git a/res/images/icon_installing_overlay04.png b/res/images/icon_installing_overlay04.png
index 48998ce..0d4608a 100644
--- a/res/images/icon_installing_overlay04.png
+++ b/res/images/icon_installing_overlay04.png
Binary files differ
diff --git a/res/images/icon_installing_overlay05.png b/res/images/icon_installing_overlay05.png
index 9f056b1..4bfacb2 100644
--- a/res/images/icon_installing_overlay05.png
+++ b/res/images/icon_installing_overlay05.png
Binary files differ
diff --git a/res/images/icon_installing_overlay06.png b/res/images/icon_installing_overlay06.png
index e5872fd..5fd2528 100644
--- a/res/images/icon_installing_overlay06.png
+++ b/res/images/icon_installing_overlay06.png
Binary files differ
diff --git a/res/images/icon_installing_overlay07.png b/res/images/icon_installing_overlay07.png
index 4ad8bf3..350b381 100644
--- a/res/images/icon_installing_overlay07.png
+++ b/res/images/icon_installing_overlay07.png
Binary files differ