This puzzle is about...
the most populous settlements in East Sussex
To start with, we note that the pictures represent the words
HILaL (i.e. the Islamic crescent, shown here on the Maldivian flag) (thanks juicifer)
bOUGH
cLEWES (Howard Clewes, one of the screenwriters for The Day They Robbed the Bank of England)
dEHAVEN (Gloria DeHaven, lead actress in Summer Holiday (1948))
eTON College
AFfORD
gLADE
PEACh (the background color is onbly for extraction purposes, this is the actual color)
URiNE
BOj
kEA (as in Mauna Kea, the highest point in Hawaii)
lEAST
SEAm
CROWn
oBEX (thanks juicifer)
HOp
qAND (the Arabic word for rock candy)
STrINGS (seen here not attached to a guitar)
sPORTS (EA Sports)
BRIGHt (Millie Bright, a member of the English women's national football team, aka the Lionesses)
BuYS
SEv
wON
VEx
HAy (as in Hay-on-Wye, a town on the border between Wales and England)
BORz (the Hungarian word for badger)
We can then
Patch together the capitalised letters according to the colour of their detailing in approximate spectral order:
BRIGH+TON+AND+HO+VE (whose pictures were augmented with RED detailing)
EAST+BO+URNE (ORANGE detailing)
HA+STINGS (YELLOW detailing)
BEX+HILL+ON+SEA (LIME GREEN detailing)
SE+AFORD (DARK GREEN detailing)
CROW+BOR+OUGH (BLUE detailing)
PORTS+LADE+BYS+EA (INDIGO detailing)
PEAC+EHAVEN (VIOLET detailing)
and um LEWES (MAGENTA detailing)
the solutions for
LEWES, HASTINGS and SEAFORD were easy to identify and satisfied a natural link.
which leaves
HAILSHAM. (A quick Google on top ten East Sussex towns leads to the wikipedia page quoted at the beginning and Hailsham is the missing entry).