diff --git a/CMakeLists.txt b/CMakeLists.txt
index ad37da7..2519a8f 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -159,6 +159,7 @@ set(SOURCES_CG
   src/r61524/r61524.c
   # Image library
   src/image/image_alloc.c
+  src/image/image_alloc_palette.c
   src/image/image_alpha.c
   src/image/image_clear.c
   src/image/image_copy.c
@@ -171,11 +172,15 @@ set(SOURCES_CG
   src/image/image_fill.c
   src/image/image_free.c
   src/image/image_get_pixel.c
-  src/image/image_palette_size.c
+  src/image/image_hflip.c
+  src/image/image_hflip_alloc.c
+  src/image/image_set_palette.c
   src/image/image_set_pixel.c
   src/image/image_sub.c
   src/image/image_target.c
   src/image/image_valid.c
+  src/image/image_vflip.c
+  src/image/image_vflip_alloc.c
   # Rendering
   src/render-cg/dclear.c
   src/render-cg/dpixel.c
diff --git a/include/gint/image.h b/include/gint/image.h
index 42519bb..e6aad53 100644
--- a/include/gint/image.h
+++ b/include/gint/image.h
@@ -314,11 +314,6 @@ int image_decode_pixel(image_t const *img, int pixel);
    image's data array, and might be much larger than the sub-image. */
 int image_data_size(image_t const *img);
 
-/* image_palette_size(): Compute the size of the [palette] array
-   This function returns the size of the palette array, in bytes. This can be
-   used to duplicate the palette. For images without a palette, returns -1. */
-int image_palette_size(image_t const *img);
-
 //---
 // Basic image modifications
 //---
@@ -457,6 +452,10 @@ image_t *image_sub(image_t const *src, int x, int y, int w, int h,
 void image_hflip(image_t const *src, image_t *dst);
 image_t *image_hflip_alloc(image_t const *src);
 
+/* image_vflip(): Flip vertically (supports in-place) */
+void image_vflip(image_t const *src, image_t *dst);
+image_t *image_vflip_alloc(image_t const *src);
+
 /* TODO: Geometric transforms */
 
 //---
diff --git a/src/image/image_alloc_palette.c b/src/image/image_alloc_palette.c
index 1afe5a2..040ba2e 100644
--- a/src/image/image_alloc_palette.c
+++ b/src/image/image_alloc_palette.c
@@ -1,30 +1,31 @@
 #include <gint/image.h>
 #include <gint/defs/util.h>
 #include <stdlib.h>
+#include <string.h>
 
 bool image_alloc_palette(image_t *img, int size)
 {
-    if(!img || !IMAGE_IS_INDEXED(img))
-        return;
-    if(img->flags & IMAGE_FLAGS_PALETTE_OWN)
+    if(!img || !IMAGE_IS_INDEXED(img->format))
+        return false;
+    if(img->flags & IMAGE_FLAGS_PALETTE_ALLOC)
         free(img->palette);
 
-    if(IMAGE_IS_P8(img)) {
+    if(IMAGE_IS_P8(img->format)) {
         size = (size <= 0) ? 256 : min(size, 256);
     }
-    if(IMAGE_IS_P4(img)) {
+    if(IMAGE_IS_P4(img->format)) {
         size = 16;
     }
 
     img->palette = calloc(size, 2);
     img->color_count = 0;
-    img->flags &= ~IMAGE_FLAGS_PALETTE_OWN;
+    img->flags &= ~IMAGE_FLAGS_PALETTE_ALLOC;
 
     if(!img->palette)
         return false;
 
     memset(img->palette, 0, 2*size);
     img->color_count = size;
-    img->flags |= IMAGE_FLAGS_PALETTE_OWN;
+    img->flags |= IMAGE_FLAGS_PALETTE_ALLOC;
     return true;
 }
diff --git a/src/image/image_hflip.c b/src/image/image_hflip.c
new file mode 100644
index 0000000..4a540c1
--- /dev/null
+++ b/src/image/image_hflip.c
@@ -0,0 +1,47 @@
+#include <gint/image.h>
+
+void image_hflip(image_t const *src, image_t *dst)
+{
+    if(!image_target(src, dst, DATA_RW, SAME_DEPTH, SAME_SIZE))
+        return;
+
+    void *src_px = src->data;
+    void *dst_px = dst->data;
+    int src_alpha = image_alpha(src->format);
+    int dst_alpha = image_alpha(dst->format);
+    int h = src->height;
+
+    if(IMAGE_IS_RGB16(src->format)) {
+        while(h-- > 0) {
+            for(int x1 = 0; x1 < (src->width + 1) >> 1; x1++) {
+                int x2 = src->width - 1 - x1;
+                int px1 = ((uint16_t *)src_px)[x1];
+                int px2 = ((uint16_t *)src_px)[x2];
+
+                if(px1 != src_alpha)
+                    ((uint16_t *)dst_px)[x2] = px1 - (px1 == dst_alpha);
+                if(px2 != src_alpha)
+                    ((uint16_t *)dst_px)[x1] = px2 - (px2 == dst_alpha);
+            }
+            src_px += src->stride;
+            dst_px += dst->stride;
+        }
+    }
+    else if(IMAGE_IS_P8(src->format)) {
+        while(h-- > 0) {
+            for(int x1 = 0; x1 < (src->width + 1) >> 1; x1++) {
+                int x2 = src->width - 1 - x1;
+
+                int px1 = ((int8_t *)src_px)[x1];
+                int px2 = ((int8_t *)src_px)[x2];
+
+                if(px1 != src_alpha)
+                    ((int8_t *)dst_px)[x2] = px1;
+                if(px2 != src_alpha)
+                    ((int8_t *)dst_px)[x1] = px2;
+            }
+            src_px += src->stride;
+            dst_px += dst->stride;
+        }
+    }
+}
diff --git a/src/image/image_hflip_alloc.c b/src/image/image_hflip_alloc.c
new file mode 100644
index 0000000..6d9f0fc
--- /dev/null
+++ b/src/image/image_hflip_alloc.c
@@ -0,0 +1,17 @@
+#include <gint/image.h>
+
+image_t *image_hflip_alloc(image_t const *src)
+{
+    if(!image_valid(src))
+        return NULL;
+
+    image_t *dst = image_alloc(src->width, src->height, src->format);
+    if(!dst || !image_copy_palette(src, dst, -1)) {
+        image_free(dst);
+        return NULL;
+    }
+
+    image_clear(dst);
+    image_hflip(src, dst);
+    return dst;
+}
diff --git a/src/image/image_palette_size.c b/src/image/image_palette_size.c
deleted file mode 100644
index 2953059..0000000
--- a/src/image/image_palette_size.c
+++ /dev/null
@@ -1,7 +0,0 @@
-#include <gint/image.h>
-
-int image_palette_size(image_t const *img)
-{
-    return (img->color_count >= 0) ? img->color_count* 2 : -1;
-}
-
diff --git a/src/image/image_set_palette.c b/src/image/image_set_palette.c
index 021b823..4da4f2c 100644
--- a/src/image/image_set_palette.c
+++ b/src/image/image_set_palette.c
@@ -3,16 +3,16 @@
 
 void image_set_palette(image_t *img, uint16_t *palette, int size, bool owns)
 {
-    if(!img || !IMAGE_IS_INDEXED(img))
+    if(!img || !IMAGE_IS_INDEXED(img->format))
         return;
-    if(img->flags & IMAGE_FLAGS_PALETTE_OWN)
+    if(img->flags & IMAGE_FLAGS_PALETTE_ALLOC)
         free(img->palette);
 
     img->palette = palette;
     img->color_count = size;
 
     if(owns)
-        img->flags |= IMAGE_FLAGS_PALETTE_OWN;
+        img->flags |= IMAGE_FLAGS_PALETTE_ALLOC;
     else
-        img->flags &= ~IMAGE_FLAGS_PALETTE_OWN;
+        img->flags &= ~IMAGE_FLAGS_PALETTE_ALLOC;
 }
diff --git a/src/image/image_vflip.c b/src/image/image_vflip.c
new file mode 100644
index 0000000..1c4f324
--- /dev/null
+++ b/src/image/image_vflip.c
@@ -0,0 +1,62 @@
+#include <gint/image.h>
+#include <stdlib.h>
+#include <string.h>
+
+static void copy_row_rgb16(uint16_t *src, uint16_t *dst, int src_alpha,
+    int dst_alpha, int width)
+{
+    for(int x = 0; x < width; x++) {
+        int px = src[x];
+        if(px != src_alpha)
+            dst[x] = px - (px == dst_alpha);
+    }
+}
+
+static void copy_row_p8(int8_t *src, int8_t *dst, int src_alpha, int width)
+{
+    for(int x = 0; x < width; x++) {
+        int px = src[x];
+        if(px != src_alpha)
+            dst[x] = px;
+    }
+}
+
+void image_vflip(image_t const *src, image_t *dst)
+{
+    if(!image_target(src, dst, DATA_RW, SAME_DEPTH, SAME_SIZE))
+        return;
+
+    int h = src->height;
+    void *src_top = src->data;
+    void *src_bot = src->data + (h - 1) * src->stride;
+    void *dst_top = dst->data;
+    void *dst_bot = dst->data + (h - 1) * dst->stride;
+
+    int src_alpha = image_alpha(src->format);
+    int dst_alpha = image_alpha(dst->format);
+
+    int row_length = src->stride;
+    void *row = malloc(row_length);
+    if(!row)
+        return;
+
+    for(int y = 0; y < (h + 1) >> 1; y++) {
+        memcpy(row, src_top, row_length);
+
+        if(IMAGE_IS_RGB16(src->format)) {
+            copy_row_rgb16(src_bot, dst_top, src_alpha, dst_alpha, src->width);
+            copy_row_rgb16(row, dst_bot, src_alpha, dst_alpha, src->width);
+        }
+        else {
+            copy_row_p8(src_bot, dst_top, src_alpha, src->width);
+            copy_row_p8(row, dst_bot, src_alpha, src->width);
+        }
+
+        src_top += src->stride;
+        src_bot -= src->stride;
+        dst_top += dst->stride;
+        dst_bot -= dst->stride;
+    }
+
+    free(row);
+}
diff --git a/src/image/image_vflip_alloc.c b/src/image/image_vflip_alloc.c
new file mode 100644
index 0000000..ef26c91
--- /dev/null
+++ b/src/image/image_vflip_alloc.c
@@ -0,0 +1,17 @@
+#include <gint/image.h>
+
+image_t *image_vflip_alloc(image_t const *src)
+{
+    if(!image_valid(src))
+        return NULL;
+
+    image_t *dst = image_alloc(src->width, src->height, src->format);
+    if(!dst || !image_copy_palette(src, dst, -1)) {
+        image_free(dst);
+        return NULL;
+    }
+
+    image_clear(dst);
+    image_vflip(src, dst);
+    return dst;
+}