diff --git a/term/src/terminalstate.rs b/term/src/terminalstate.rs
index 837b7d94b..4d78ace06 100644
--- a/term/src/terminalstate.rs
+++ b/term/src/terminalstate.rs
@@ -1326,6 +1326,7 @@ impl TerminalState {
             return;
         }
 
+        // FIXME: cache recent images and avoid assigning a new id for repeated data!
         let image_data = Arc::new(ImageData::with_raw_data(png_image_data));
         self.assign_image_to_cells(width, height, image_data);
     }
@@ -1343,9 +1344,9 @@ impl TerminalState {
         let cursor_x = self.cursor.x;
         let x_delta = 1.0 / (width as f32 / (self.pixel_width as f32 / physical_cols as f32));
         let y_delta = 1.0 / (height as f32 / (self.pixel_height as f32 / physical_rows as f32));
-        debug!(
-            "image is {}x{} cells, {}x{} pixels",
-            width_in_cells, height_in_cells, width, height
+        log::error!(
+            "image is {}x{} cells, {}x{} pixels, x_delta:{} y_delta:{}",
+            width_in_cells, height_in_cells, width, height, x_delta, y_delta,
         );
         for _ in 0..height_in_cells {
             let mut xpos = NotNan::new(0.0).unwrap();
diff --git a/wezterm/src/gui/fragment.glsl b/wezterm/src/gui/fragment.glsl
index 521ad1724..59a450979 100644
--- a/wezterm/src/gui/fragment.glsl
+++ b/wezterm/src/gui/fragment.glsl
@@ -1,18 +1,19 @@
 precision highp float;
 
-in vec2 o_tex;
-in vec4 o_fg_color;
-in vec4 o_bg_color;
-in float o_has_color;
-in vec3 o_hsv;
-in vec2 o_underline;
-in vec2 o_cursor;
-in vec4 o_cursor_color;
+varying float o_has_color;
+varying vec2 o_cursor;
+varying vec2 o_tex;
+varying vec2 o_underline;
+varying vec3 o_hsv;
+varying vec4 o_bg_color;
+varying vec4 o_cursor_color;
+varying vec4 o_fg_color;
 
 uniform mat4 projection;
 uniform bool window_bg_layer;
 uniform bool bg_and_line_layer;
 uniform bool has_background_image;
+
 uniform sampler2D atlas_nearest_sampler;
 uniform sampler2D atlas_linear_sampler;
 
diff --git a/wezterm/src/gui/vertex.glsl b/wezterm/src/gui/vertex.glsl
index ad683fefe..89bfbed37 100644
--- a/wezterm/src/gui/vertex.glsl
+++ b/wezterm/src/gui/vertex.glsl
@@ -1,28 +1,29 @@
 precision highp float;
-in vec2 position;
-in vec2 adjust;
-in vec2 tex;
-in vec2 underline;
-in vec4 bg_color;
-in vec4 fg_color;
-in float has_color;
-in vec2 cursor;
-in vec4 cursor_color;
-in vec3 hsv;
+
+attribute vec2 position;
+attribute vec2 adjust;
+attribute vec2 tex;
+attribute vec2 underline;
+attribute vec4 bg_color;
+attribute vec4 fg_color;
+attribute float has_color;
+attribute vec2 cursor;
+attribute vec4 cursor_color;
+attribute vec3 hsv;
 
 uniform mat4 projection;
 uniform bool window_bg_layer;
 uniform bool bg_and_line_layer;
 uniform bool has_background_image;
 
-out vec2 o_tex;
-out vec4 o_fg_color;
-out vec4 o_bg_color;
-out float o_has_color;
-out vec2 o_underline;
-out vec2 o_cursor;
-out vec4 o_cursor_color;
-out vec3 o_hsv;
+varying float o_has_color;
+varying vec2 o_cursor;
+varying vec2 o_tex;
+varying vec2 o_underline;
+varying vec3 o_hsv;
+varying vec4 o_bg_color;
+varying vec4 o_cursor_color;
+varying vec4 o_fg_color;
 
 // Returns a position that is outside of the viewport,
 // such that this vertex effectively won't contribute