TF-761 Add adr for down size of base64

docs/adr/0011-down-size-of-base64-image.md

@@ -0,0 +1,23 @@
+# 11. down-size-of-base64-image
+
+Date: 2022-07-28
+
+## Status
+
+Accepted
+
+## Context
+
+For large images (several MB or more) converting to base64 will take a long time and exceed the storage limit of the string. 
+Leads to long waits on the main thread, causing a feeling of not being smooth on mobile devices with weak configuration.
+
+## Decision
+
+We can reduce the image `size` and `quality` when displaying.
+- For mobile: 
+  + Use [flutter_image_compress](https://pub.dev/packages/flutter_image_compress) to compress image use native (Objective-C/Kotlin) with faster speed.
+
+## Consequences
+
+- The size of the image has been significantly reduced with the display quality not much different from the original image.
+- Faster processing speed.