Device name: Nexus 6P
Application version: Canary 58.0.2992.0
Operating system: Android 7.1.1; Nexus 6P/Build N4F26J
Flags: #data-reduction-proxy-lo-fi set to "Always on", assuming this happens with 'Enabled' in slow connections

Steps to reproduce:
(1) Open an app which uses Chrome Custom Tabs (I used Reddit)
(2) Click on a link to a page with images
(3) Find an image which has been replaced by LoFi
(4) Long press on the image

Example URLs:
Post on the Reddit App
https://www.reddit.com/r/news/comments/5q5615/trump_orders_wall_to_be_built_on_mexico_border/
Target URL
http://www.bbc.com/news/world-us-canada-38740717

Expected result:
Context menu should be shown, so I can load the replaced image.

Actual result:
The long press gesture is detected (image is highlighted, phone vibrates) but no context menu is shown. It is shown for linked images, but only showing Link options (no Image options).