Vimcal - Vimcal is the world’s fastest calendar, beautifully designed for people who work remotely and live in their calendars.
Hover Zoom - Enlarge thumbnails on mouse over.
Button for Google Calendar™ - See your daily schedule and join meetings in one-click.
Imagus - The extension is intended to complement image features that (I think) is missing from Opera by...
Calendarist - Time blocking companion for Google Calendar
Image Max URL - Help find larger or original versions of images, including a customizable image popup feature