There are 17 F-15’s exhaust engine nozzles in this image.
The photo in this article was posted by the 48th Fighter Wing on their FB page. It shows at least 17 complete exhaust engine nozzles for the F100-PW-220 and F100-PW-220-229 engines of the F-15C, D and E jets based at RAF Lakenheath, UK.
You can clearly see the typical convergent-divergent profile of the axially symmetrical exhaust nozzles, the nozzle actuators and the titanium actuating rods.
Noteworthy, unlike many other supersonic aircraft’s jet engines, the PW-220 and -229 are “exposed” and lack the so-called “Turkey Feathers” cover plates. These covers were removed in the 1970s to make maintenance easier on U.S. Eagle jets; the Israeli F-15Is, that are equipped with the same engines, or the F-15K Slam Eagles (the Strike Eagle version for the Republic of Korea Air Force) still use them.
The one depicted in the image must be a part of the Engine Shop of the 48th CMS (Component Maintenance Squadron), one of the units of the 48th FW, responsible for on-equipment and off-equipment maintenance and accessory repair of F-15C, F-15D, F-15E and HH-60G aircraft.
According to the unit’s Factsheets, among all the other things, the 48th CMS also manages equipment calibrations and intermediate level maintenance on F-15C, F-15D, F-15E and C-130 avionics line replaceable units; F-15E, F-16, and A-10 LANTIRN navigation, targeting and reconnaissance pods as well as F100-PW-220 and F100-PW-220-229 engines.
Image credit: 48th FW
These are -229 variants, from the triangular pattern on the burner casing.
Those are called chem milled ducts and both -220 and -229 engines use them.
These augmentors are lacking turkey feathers because they are slated for F15 aircraft. On F16’s the engines still use them no matter if it’s a -220 or -229.