diff --git a/internal/graphics/framebuffer.go b/internal/graphics/framebuffer.go
index 320dcc2ee..f8999c55e 100644
--- a/internal/graphics/framebuffer.go
+++ b/internal/graphics/framebuffer.go
@@ -70,11 +70,8 @@ func newScreenFramebuffer(width, height int) *framebuffer {
 
 // defaultViewportSize is the default size (width or height) of viewport.
 //
-// defaultViewportSize also represents the maximum size of a framebuffer
-// and of an Image (it is used to declare MaxImageSize).
-//
-// For portability reasons it must be a power of two.
-const defaultViewportSize = 8192
+// defaultViewportSize also represents the maximum size of a framebuffer.
+const defaultViewportSize = 4096
 
 // viewportSize returns the viewport size of the framebuffer.
 func (f *framebuffer) viewportSize() (int, int) {