diff --git a/data/shaders/drawimage.frag b/data/shaders/drawimage.frag
index 87a96aa1eb..c4ae8ce042 100644
--- a/data/shaders/drawimage.frag
+++ b/data/shaders/drawimage.frag
@@ -6,8 +6,9 @@ uniform usampler2DArray uTexture;
 flat in ivec4           fClip;
 flat in int             fFlags;
 in vec4                 fColour;
-flat in int             fTexAtlasIndex;
+flat in int             fTexColourAtlas;
 in vec2                 fTexColourCoords;
+flat in int             fTexMaskAtlas;
 in vec2                 fTexMaskCoords;
 flat in int             fMask;
 
@@ -24,8 +25,8 @@ void main()
         discard;
     }
 
-    vec4 mask = uPalette[texture(uTexture, vec3(fTexMaskCoords, float(fTexAtlasIndex))).r];
-    vec4 texel = uPalette[texture(uTexture, vec3(fTexColourCoords, float(fTexAtlasIndex))).r];
+    vec4 texel = uPalette[texture(uTexture, vec3(fTexColourCoords, float(fTexColourAtlas))).r];
+    vec4 mask = uPalette[texture(uTexture, vec3(fTexMaskCoords, float(fTexMaskAtlas))).r];
 
     if (fMask != 0)
     {
diff --git a/data/shaders/drawimage.vert b/data/shaders/drawimage.vert
index 0ff5c67588..064a5e3e56 100644
--- a/data/shaders/drawimage.vert
+++ b/data/shaders/drawimage.vert
@@ -3,8 +3,9 @@
 uniform ivec2 uScreenSize;
 
 in ivec4 ivClip;
-in int   ivTexAtlasIndex;
+in int   ivTexColourAtlas;
 in vec4  ivTexColourBounds;
+in int   ivTexMaskAtlas;
 in vec4  ivTexMaskBounds;
 in int   ivFlags;
 in vec4  ivColour;
@@ -18,8 +19,9 @@ out vec2       fPosition;
 flat out ivec4 fClip;
 flat out int   fFlags;
 out vec4       fColour;
-flat out int   fTexAtlasIndex;
+flat out int   fTexColourAtlas;
 out vec2       fTexColourCoords;
+flat out int   fTexMaskAtlas;
 out vec2       fTexMaskCoords;
 flat out int   fMask;
 
@@ -60,7 +62,8 @@ void main()
     fFlags = ivFlags;
     fColour = ivColour;
     fMask = ivMask;
-    fTexAtlasIndex = ivTexAtlasIndex;
+    fTexColourAtlas = ivTexColourAtlas;
+    fTexMaskAtlas = ivTexMaskAtlas;
 
     gl_Position = vec4(pos, 0.0, 1.0);
 }
diff --git a/src/drawing/engines/opengl/DrawImageShader.cpp b/src/drawing/engines/opengl/DrawImageShader.cpp
index 7d2b3b1d81..69c6b8d6ba 100644
--- a/src/drawing/engines/opengl/DrawImageShader.cpp
+++ b/src/drawing/engines/opengl/DrawImageShader.cpp
@@ -36,8 +36,9 @@ DrawImageShader::DrawImageShader() : OpenGLShaderProgram("drawimage")
 
     glBindBuffer(GL_ARRAY_BUFFER, _vboInstances);
     glVertexAttribIPointer(vClip, 4, GL_INT, sizeof(DrawImageInstance), (void*) offsetof(DrawImageInstance, clip));
-    glVertexAttribIPointer(vTexAtlasIndex, 1, GL_INT, sizeof(DrawImageInstance), (void*) offsetof(DrawImageInstance, texAtlasIndex));
+    glVertexAttribIPointer(vTexColourAtlas, 1, GL_INT, sizeof(DrawImageInstance), (void*) offsetof(DrawImageInstance, texColourAtlas));
     glVertexAttribPointer(vTexColourBounds, 4, GL_FLOAT, GL_FALSE, sizeof(DrawImageInstance), (void*) offsetof(DrawImageInstance, texColourBounds));
+    glVertexAttribIPointer(vTexMaskAtlas, 1, GL_INT, sizeof(DrawImageInstance), (void*) offsetof(DrawImageInstance, texMaskAtlas));
     glVertexAttribPointer(vTexMaskBounds, 4, GL_FLOAT, GL_FALSE, sizeof(DrawImageInstance), (void*) offsetof(DrawImageInstance, texMaskBounds));
     glVertexAttribIPointer(vFlags, 1, GL_INT, sizeof(DrawImageInstance), (void*) offsetof(DrawImageInstance, flags));
     glVertexAttribPointer(vColour, 4, GL_FLOAT, GL_FALSE, sizeof(DrawImageInstance), (void*) offsetof(DrawImageInstance, colour));
@@ -46,8 +47,9 @@ DrawImageShader::DrawImageShader() : OpenGLShaderProgram("drawimage")
 
     glEnableVertexAttribArray(vIndex);
     glEnableVertexAttribArray(vClip);
-    glEnableVertexAttribArray(vTexAtlasIndex);
+    glEnableVertexAttribArray(vTexColourAtlas);
     glEnableVertexAttribArray(vTexColourBounds);
+    glEnableVertexAttribArray(vTexMaskAtlas);
     glEnableVertexAttribArray(vTexMaskBounds);
     glEnableVertexAttribArray(vFlags);
     glEnableVertexAttribArray(vColour);
@@ -55,8 +57,9 @@ DrawImageShader::DrawImageShader() : OpenGLShaderProgram("drawimage")
     glEnableVertexAttribArray(vMask);
 
     glVertexAttribDivisor(vClip, 1);
-    glVertexAttribDivisor(vTexAtlasIndex, 1);
+    glVertexAttribDivisor(vTexColourAtlas, 1);
     glVertexAttribDivisor(vTexColourBounds, 1);
+    glVertexAttribDivisor(vTexMaskAtlas, 1);
     glVertexAttribDivisor(vTexMaskBounds, 1);
     glVertexAttribDivisor(vFlags, 1);
     glVertexAttribDivisor(vColour, 1);
@@ -84,8 +87,9 @@ void DrawImageShader::GetLocations()
 
     vIndex              = GetAttributeLocation("vIndex");
     vClip               = GetAttributeLocation("ivClip");
-    vTexAtlasIndex      = GetAttributeLocation("ivTexAtlasIndex");
+    vTexColourAtlas     = GetAttributeLocation("ivTexColourAtlas");
     vTexColourBounds    = GetAttributeLocation("ivTexColourBounds");
+    vTexMaskAtlas       = GetAttributeLocation("ivTexMaskAtlas");
     vTexMaskBounds      = GetAttributeLocation("ivTexMaskBounds");
     vFlags              = GetAttributeLocation("ivFlags");
     vColour             = GetAttributeLocation("ivColour");
diff --git a/src/drawing/engines/opengl/DrawImageShader.h b/src/drawing/engines/opengl/DrawImageShader.h
index 425735ffa7..f4609bf581 100644
--- a/src/drawing/engines/opengl/DrawImageShader.h
+++ b/src/drawing/engines/opengl/DrawImageShader.h
@@ -24,8 +24,9 @@
 // Per-instance data for images
 struct DrawImageInstance {
     vec4i clip;
-    int texAtlasIndex;
+    int texColourAtlas;
     vec4f texColourBounds;
+    int texMaskAtlas;
     vec4f texMaskBounds;
     int flags;
     vec4f colour;
@@ -42,8 +43,9 @@ private:
 
     GLuint vIndex;
     GLuint vClip;
-    GLuint vTexAtlasIndex;
+    GLuint vTexColourAtlas;
     GLuint vTexColourBounds;
+    GLuint vTexMaskAtlas;
     GLuint vTexMaskBounds;
     GLuint vFlags;
     GLuint vColour;
diff --git a/src/drawing/engines/opengl/OpenGLDrawingEngine.cpp b/src/drawing/engines/opengl/OpenGLDrawingEngine.cpp
index 668aa91a67..2d06e255c2 100644
--- a/src/drawing/engines/opengl/OpenGLDrawingEngine.cpp
+++ b/src/drawing/engines/opengl/OpenGLDrawingEngine.cpp
@@ -952,8 +952,9 @@ void OpenGLDrawingContext::FlushImages() {
         DrawImageInstance instance;
 
         instance.clip = {command.clip[0], command.clip[1], command.clip[2], command.clip[3]};
-        instance.texAtlasIndex = command.texColour.index;
+        instance.texColourAtlas = command.texColour.index;
         instance.texColourBounds = command.texColour.normalizedBounds;
+        instance.texMaskAtlas = command.texMask.index;
         instance.texMaskBounds = command.texMask.normalizedBounds;
         instance.flags = command.flags;
         instance.colour = command.colour;