Smarthistory is an excellent free resource which I have used extensively. Created by art history lecturers Dr Beth Harris and Dr Steven Zucker, it is the official partner for art history to Khan Academy, an on-line American non-profit educational organization founded by Salman Khan in 2008.
Smarthistory has produced an extensive number of videos featuring ‘conversations’ about a work of art or architecture, with the voices of Beth and Steven, recorded on location in front of the original work in various parts of the world. For example, you might like to look at Las Meninas by Velazquez, (https://www.khanacademy.org/humanities/ap-art-history/early-europe-and-colonial-americas/reformation-counter-reformation/v/vel-zquez-las-meninas-c-1656) to complement the the lecture given by Dr Jacqueline Cockburn on this site.
I first used these short videos when taking The Arts Society course In the Footsteps of Gombrich which ran in Truro a few years ago. More recently, I have looked at them closely before going on art orientated holidays in Italy. Last September in Venice, my geek of a husband used a Khan Academy video in conjunction with headphones to play the video on his phone as he stood in front of a piece of art in a church or museum. Of course, if you are interested in coming on our visit to Vienna in May 2021 (http://theartssocietyfalmouth.org/downloads/2019-2020/VIENNAKLIMTTASFALMOUTH.pdf) you will find information to whet your appetite from Smarthistory by searching for ‘Smarthistory Gustav Klimt’ and ‘Smarthistory Vienna Seccession’.
In addition to these short videos, Smarthistory also offers a number of online courses which you can access on https://smarthistory.org/overview/courses-and-syllabi/
Happy surfing, stay well