diff --git a/src/opengl/qopengltextureuploader.cpp b/src/opengl/qopengltextureuploader.cpp
index 3dca0a43..5d650523 100644
--- a/src/opengl/qopengltextureuploader.cpp
+++ b/src/opengl/qopengltextureuploader.cpp
@@ -246,17 +246,24 @@ qsizetype QOpenGLTextureUploader::textureImage(GLenum target, const QImage &imag
             // Always needs conversion
             break;
         } else if (options & UseRedForAlphaAndLuminanceBindOption) {
             externalFormat = internalFormat = GL_RED;
             pixelType = GL_UNSIGNED_BYTE;
             targetFormat = image.format();
-        } else if (context->isOpenGLES() || context->format().profile() != QSurfaceFormat::CoreProfile) {
+        } else if ((context->isOpenGLES() && context->format().majorVersion() < 3)
+                   || (!context->isOpenGLES() && context->format().profile() != QSurfaceFormat::CoreProfile
+                       && !funcs->hasOpenGLExtension(QOpenGLExtensions::TextureSwizzle))) {
+            // qt6-base-fourier: only true ES 2 (or pre-3.3 desktop
+            // compat without the swizzle extension) reaches the
+            // GL_ALPHA fallback. ES 3+ falls through to the swizzle
+            // path below — TextureSwizzle is core in ES 3.0.
             externalFormat = internalFormat = GL_ALPHA;
             pixelType = GL_UNSIGNED_BYTE;
             targetFormat = image.format();
-        } else if (funcs->hasOpenGLExtension(QOpenGLExtensions::TextureSwizzle)) {
+        } else if (funcs->hasOpenGLExtension(QOpenGLExtensions::TextureSwizzle)
+                   || (context->isOpenGLES() && context->format().majorVersion() >= 3)) {
             funcs->glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_SWIZZLE_R, GL_ALPHA);
             funcs->glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_SWIZZLE_G, GL_ZERO);
             funcs->glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_SWIZZLE_B, GL_ZERO);
             funcs->glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_SWIZZLE_A, GL_ZERO);
             externalFormat = internalFormat = GL_RED;
             pixelType = GL_UNSIGNED_BYTE;
@@ -268,13 +275,18 @@ qsizetype QOpenGLTextureUploader::textureImage(GLenum target, const QImage &imag
             // Always needs conversion
             break;
         } else if (options & UseRedForAlphaAndLuminanceBindOption) {
             externalFormat = internalFormat = GL_RED;
             pixelType = GL_UNSIGNED_BYTE;
             targetFormat = image.format();
-        } else if (context->isOpenGLES() || context->format().profile() != QSurfaceFormat::CoreProfile) {
+        } else if ((context->isOpenGLES() && context->format().majorVersion() < 3)
+                   || (!context->isOpenGLES() && context->format().profile() != QSurfaceFormat::CoreProfile
+                       && !funcs->hasOpenGLExtension(QOpenGLExtensions::TextureSwizzle))) {
+            // qt6-base-fourier: same reasoning as the Format_Alpha8
+            // branch above — GL_LUMINANCE is also gone from ES 3
+            // glTexImage2D internalFormats.
             externalFormat = internalFormat = GL_LUMINANCE;
             pixelType = GL_UNSIGNED_BYTE;
             targetFormat = image.format();
         } else if (funcs->hasOpenGLExtension(QOpenGLExtensions::TextureSwizzle)) {
             funcs->glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_SWIZZLE_R, GL_RED);
             funcs->glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_SWIZZLE_G, GL_RED);