On-loan Rangers striker Cummings' future at Ibrox remains to be decided.
Cummings, 22, remains on loan at Rangers from English Championship side Nottingham Forest, but a decision is yet to be made regarding the two-time Scotland international's future at the club.
The Gers have already made Jamie Murphy's loan a permanent one from Brighton, while Steven Gerrard has also given his blessing for director of football Mark Allen to complete moves for Allan McGregor and Scott Arfield.
But Cummings will not have done himself any favours by posing for a photo alongside friends and Hoops midfielder Allan, which he then in turn posted on Instagram, risking the wrath of his own side's fanbase.
During his loan spell at Rangers, Cummings made 18 appearances for the Gers in all competitions and scored six goals, as he was made to act as Alfredo Morelos' back-up for most of his spell in Glasgow.
Cummings is not the only loan player awaiting a decision over a possible permanent deal, with Russell Martin on loan from Norwich City. However, Sean Goss has been told he can return to QPR, which he confirmed on Instagram.