diff --git a/README.md b/README.md
index a547292f..908ee5c2 100644
--- a/README.md
+++ b/README.md
@@ -58,6 +58,7 @@ Some models, like [andreasjansson/blip-2](https://replicate.com/andreasjansson/b
 To run a model that takes a file input,
 pass a URL to a publicly accessible file.
 Or, for smaller files (<10MB), you can pass a file handle directly.
+If you don't use the built-in file handler but want to pass a file handle directly, you'll need to create a base64 encoded data URL of the file input.
 
 ```python
 >>> output = replicate.run(