diff --git a/CHANGELOG.md b/CHANGELOG.md
index ea837e3d0b..6cd388d0d7 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,6 +8,7 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 - Fix concurrent first access to lazily initialized graph object properties, which could raise `ValueError("Invalid value")` [[#5691](https://github.com/plotly/plotly.py/pull/5691)], with thanks to @hb1915 for the contribution!
 - Fix `mpl_to_plotly` crashing on touching bars (such as `plt.hist`) due to floating-point noise producing negative `bargap` values by clamping `bargap` to `[0, 1]` [[#5696](https://github.com/plotly/plotly.py/pull/5696)], with thanks to @robertoffmoura for the contribution!
 - Fix `px.sunburst`, `px.treemap` and `px.icicle` listing sectors in a different order on every run when `path` is used with a Polars DataFrame; sectors now follow their order of first appearance for all dataframe backends [[#5766](https://github.com/plotly/plotly.py/pull/5766)], with thanks to @Irahan2 for the contribution!
+- Fix `px.imshow` ignoring `aspect="auto"` for RGB and RGBA images, which kept their pixels square instead of stretching the image to fill the axes [[#5788](https://github.com/plotly/plotly.py/pull/5788)], with thanks to @jayzhou2309 for the contribution!
 
 ## [7.1.0] - 2026-09-15
 
diff --git a/plotly/express/_imshow.py b/plotly/express/_imshow.py
index 576b114d51..c0229b0cc2 100644
--- a/plotly/express/_imshow.py
+++ b/plotly/express/_imshow.py
@@ -631,6 +631,9 @@ def imshow(
     if animation_frame:
         fig.frames = frame_list
     fig.update_layout(layout)
+    if trace["type"] == "image" and aspect == "auto":
+        # plotly.js anchors the y axis of an image trace to its x axis by default
+        fig.update_yaxes(scaleanchor=False)
     # Hover name, z or color
     if binary_string and rescale_image and not np.all(img == img_rescaled):
         # we rescaled the image, hence z is not displayed in hover since it does
diff --git a/tests/test_optional/test_px/test_imshow.py b/tests/test_optional/test_px/test_imshow.py
index 3a0e230eb9..79618310c5 100644
--- a/tests/test_optional/test_px/test_imshow.py
+++ b/tests/test_optional/test_px/test_imshow.py
@@ -414,6 +414,15 @@ def test_imshow_hovertemplate(binary_string):
         )
 
 
+@pytest.mark.parametrize("binary_string", [False, True])
+def test_image_trace_aspect(binary_string):
+    img = np.zeros((2, 10, 10, 3), dtype=np.uint8)
+    fig = px.imshow(img, facet_col=0, aspect="auto", binary_string=binary_string)
+    assert [ax.scaleanchor for ax in fig.select_yaxes()] == [False, False]
+    fig = px.imshow(img, facet_col=0, binary_string=binary_string)
+    assert [ax.scaleanchor for ax in fig.select_yaxes()] == [None, None]
+
+
 @pytest.mark.parametrize("facet_col", [0, 1, 2, -1])
 @pytest.mark.parametrize("binary_string", [False, True])
 def test_facet_col(facet_col, binary_string):