Fix some background pgd not works

src/scripts/softpal/img/pgd/base.rs

@@ -14,11 +14,11 @@ pub struct PgdGeHeader {
     pub offset_y: u32,
     pub width: u32,
     pub height: u32,
-    // untested
     pub canvas_width: u32,
-    // untested
     pub canvas_height: u32,
-    pub mode: u32,
+    pub mode: u16,
+    // Some background image has this (0xF)
+    pub _unk: u16,
 }
 
 impl PgdGeHeader {
@@ -47,7 +47,7 @@ pub struct PgdReader<T: Read + Seek> {
     width: u32,
     height: u32,
     bpp: u8,
-    method: u32,
+    method: u16,
     format: Option<ImageColorType>,
 }
 

src/scripts/softpal/img/pgd/ge.rs

@@ -69,6 +69,7 @@ impl ScriptBuilder for PgdGeBuilder {
             canvas_width: data.width,
             canvas_height: data.height,
             mode: 3,
+            _unk: 0,
         };
         writer.write_all(b"GE \0")?;
         header.pack(&mut writer, false, Encoding::Utf8)?;