Thank you!https://www.backyardchickens.com/articles/bumblefoot-treatment.72887/ <-- There is some info on Bumblefoot from a BYC article. This article defines bumblefoot and gives a non-surgical approach to treatment.
Your bumblefoot case doesn't look terribly advanced. My local vet (who specializes in expensive birds) tells me that surgery (which is frequently recommended online) can actually worsen bumblefoot. I can tell you in my own singular experience, surgery did not work. Nor did soaking with Epson salts alone, but by the time I did treat soaking, the bumblefoot was quite advanced.
I currently have two chickens with bumblefoot (both of which I've tried the aforementioned treatments with the aforementioned results) and have seen radical improvement using an oral antibiotic, and wrapping the foot with vet wrap and silver sulfadiazine cream. I've been doing this for three weeks, and jus this week the bumblefoot plug fell out of one of the hens feet, and I have seen a marked improvement in swelling.
The oral antibiotic I am using is called Baytril, available here: https://allbirdproducts.com/products/baytril-2-5
The antibiotic comes with a syringe and you squirt some in the chicken's mouth once a day. The amount varies based on the weight of the chicken, so you'll need to weigh the chicken to calculate the dosage, but it should be around .25-3.0 mL.
The silver sulfadiazine cream is available at Tractor Supply. You can also use a triple antibiotic ointment. The idea really is to keep the plug moist, so it can work itself out. I applied the cream every 2-3 days and re-wrapped the foot each night.
Many folks have had success with many treatments, so I am only sharing one opinion. However I have not had success with any treatment, and trust me I've tried them all, except for what I've discussed here.