Table 1 Composition of the standard set of photographs (n  =  50) by clinical signs and algorithms.

Number	Sign/algorithm	Total positive photographs
01	Pus	22 (44)
02	Redness:
	Exact (none, mild, moderate, severe)	†
	Binary (moderate or severe v none or mild)*	19 (38)
03	Swelling:
	Exact (none, mild, moderate, severe)	‡
	Binary (moderate or severe v none or mild)*	23 (46)
04	Redness or swelling (moderate or severe)	25 (50)
05	Redness and swelling (moderate or severe)	17 (34)
06	Pus and (redness or swelling (moderate or severe))	13 (26)
07	Pus and redness (moderate or severe)	7 (14)
08	Pus and (redness and swelling (any degree))	21 (22)
09	Pus and (redness and swelling (moderate or severe))	7 (14)
10	(Pus and moderate redness) or (severe redness)	9 (18)
	Negative: no pus, no moderate/severe redness/swelling	16 (32)

Values in parentheses are percentages.

*Ratings of none or mild, and moderate or severe were combined into single values (0 and 1 respectively).

†Number of photographs by category of redness: none, 14; mild, 17; moderate, 15; severe, 4.

‡Number of photographs by category of swelling: none, 6; mild, 21; moderate, 22; severe, 1.