diff --git a/README.md b/README.md
index f466196..c8cb419 100644
--- a/README.md
+++ b/README.md
@@ -37,7 +37,7 @@ Public `Graphik` methods:
 - `drawRectangle(xpos, ypos, width, height, color)` — `xpos`/`ypos` are the rectangle's top-left corner.
 - `drawText(text, xpos, ypos, size, color)` — `xpos`/`ypos` are the **center** of the rendered text, not its top-left corner. This differs from `drawRectangle`, `drawButton` and `drawImage`, which all position their top-left corner at the given coordinates.
 - `drawButton(xpos, ypos, width, height, colorBox, colorText, sizeText, text, function)` — draws a rectangle and centered text, and calls `function()` on every call where the mouse is held inside the button with button 1 down (there is no click-edge detection, so a held-down mouse fires `function()` once per call, not once per click). Callers wanting once-per-click semantics must debounce on their side. The clickable region is exactly the drawn box — `xpos` through `xpos + width - 1`, and `ypos` through `ypos + height - 1` — so buttons laid out edge to edge share no clickable coordinate.
-- `drawImage(filePath, xpos, ypos, width, height)` — caches the loaded and scaled surface by `filePath`, so an image edited on disk mid-run will not be picked up until the process restarts.
+- `drawImage(filePath, xpos, ypos, width, height)` — caches the loaded and scaled surface by `filePath`, so an image edited on disk mid-run will not be picked up until the process restarts. Only the most recently requested size is kept per path, so drawing the same file at two alternating sizes rescales it on every call.
 
 Color constants: `Graphik.black`, `Graphik.white`, `Graphik.red`, `Graphik.green`, `Graphik.blue`.
 
diff --git a/src/main/python/preponderous/graphik/graphik.py b/src/main/python/preponderous/graphik/graphik.py
index 63e1498..37003dd 100644
--- a/src/main/python/preponderous/graphik/graphik.py
+++ b/src/main/python/preponderous/graphik/graphik.py
@@ -192,6 +192,10 @@ def drawImage(self, filePath, xpos, ypos, width, height):
         restarts. A path that fails to load caches nothing and raises on every
         call.
 
+        Only the most recently requested size is kept per path: drawing the
+        same file at a different size rescales it and replaces the cached
+        scale, so alternating between two sizes rescales on every call.
+
         Args:
             filePath: Path to the image file, used as the cache key.
             xpos: X coordinate of the image's left edge, in pixels.