Update README.md

README.md

@@ -147,6 +147,7 @@ Unfortunately, these images were too large to upload easily.
 Therefore, images were automatically subdivided in half if they were above 12,000 pixels in either height or width. 
 Subdivided images were also tagged with additional metadata, such that users can reconstruct the original images if they would prefer.
 Otherwise, metadata was copied across subdivided images.
+Additionally, images were converted from RGB/RGBX `.tiff` to RGB `.png` files to avoid encoding issues.
 This process resulted in 2,706 final deep space images.