Table 3.

Correlations of photo features with engagement.

Kind	Feature	Like	Comment	Engagement
Face features	Number of faces	0.003	0.005	0.003
	Closeup	−0.005	0.011 *	−0.005
	Face ratio	−0.006	0.010 *	−0.006
	Age	0.008 *	−0.001	0.008 *
	Female	−0.001	0.014 *	0.000
	Anger	−0.001	−0.005	−0.001
	Contempt	0.004	0.004	0.004
	Disgust	0.001	0.008 *	0.002
	Fear	0.000	−0.002	0.000
	Happiness	−0.005	0.008 *	−0.005
	Sadness	−0.002	0.007 *	−0.002
	Surprise	0.002	0.002	0.002
	Neutral	0.021 *	0.010 *	0.021 *
OCR feature	Number of words	0.011 *	0.035 *	0.012 *
Pixel features	Red mean	0.024 *	0.021 *	0.025 *
	Red var	−0.004	−0.013 *	−0.004
	Green mean	0.028 *	0.023 *	0.028 *
	Green var	0.001	−0.011 *	0.000
	Blue mean	0.027 *	0.025 *	0.028 *
	Blue var	0.008 *	−0.009 *	0.008 *
	Saturation mean	−0.028 *	−0.030 *	−0.028 *
	Saturation var	−0.007 *	−0.025 *	−0.008 *
	Value mean	0.020 *	0.018 *	0.020 *
	Value var	−0.001	−0.007 *	−0.001
	Red share	−0.010 *	−0.004	−0.010 *
	Orange share	−0.021 *	−0.010 *	−0.021 *
	Yellow share	−0.014 *	−0.011 *	−0.014 *
	Green share	−0.020 *	−0.023 *	−0.021 *
	Blue share	−0.012 *	−0.008 *	−0.012 *
	Violet share	-	-	-
	Share of warm colors	−0.025 *	−0.014 *	−0.025 *
	Share of cold colors	−0.023 *	−0.021 *	−0.023 *
	Hue peaks	−0.003	−0.015 *	−0.003
	Pleasure	0.013 *	0.010 *	0.013 *
	Arousal	−0.030 *	−0.031 *	−0.031 *
	Dominance	−0.026 *	−0.025 *	−0.026 *
Visual features	Brightness	0.027 *	0.024 *	0.028 *
	Colorfulness	−0.022 *	−0.028 *	−0.022 *
	Naturalness	0.000	−0.009 *	0.000
	Contrast	0.006	−0.004	0.006
	RGB Contrast	0.001	−0.010 *	0.001
	Sharpness	−0.005	0.020 *	−0.005
	Color diversity	0.008 *	−0.021 *	0.007 *
	Color harmony	0.011 *	−0.004	0.011 *

* p < 0.05.