First, we're sorry for the error you're having with the photo editor. There will be an upgrade later this year, so we are stuck with this intermittent error for now.
The editor seems confused when you attempt to edit the same photo for a second time in a given session.
The Photo Editor error typically looks like this:
The image fails to load
The available icons (stickers) fail to load
The Workaround
Clearing the web browser's cached data, as described below for each browser (Chrome, Firefox, Safari), is a relatively simple workaround for restoring the photo editor to a working state.
Google Chrome
Open Chrome.
Press Ctrl + Shift + Delete (Windows) or Command + Shift + Delete (Mac) to open the "Clear browsing data" window.
Select Cached images and files (uncheck other options just to clear the cache).
Choose the time range (e.g., "One hour").
Click Clear data.
Video:
Mozilla Firefox
Open Firefox.
Press Ctrl + Shift + Delete (Windows) or Command + Shift + Delete (Mac) to open the "Clear Recent History" window.
Select Cache (uncheck other options to only clear the cache).
Choose the time range (e.g., "1 hour").
Click OK or Clear Now.
Video:
Safari
Open Safari.
Enable the Developer menu if not already visible: Go to Safari > Preferences > Advanced, and check Show Develop menu in menu bar.
Click Develop in the menu bar.
Select Empty Caches to clear the cache.
Alternatively, via keyboard shortcut:
Press Option + Command + E to empty the cache directly.
Video: