This picture used the contrast with size, there are two different size element in one picture and this successfully emphasized the pyramid is much bigger than the human.
This picture used the contrast with tunnel value, the light coming in from outside of the cave created a idea that the cave is darker than the outside, and the light in coming in from the outside.
This picture used the contrast with typeface, although the designer used the same font for every words but the designer used bold for the word "Celebration" as to emphasize on the title in order to catch audience
attention.
This picture used the contrast with color to emphasize on the main object that the picture want to show, with the use of contrast in color the capsicum is outstanding than those green apple.
References:
Picture 1:
GRAPHIC DESIGN: The UNITY/EMPHASIS Ads, (N.D) [Online Picture]. Retrieved from http://www.highlandtechnology.org/files/graphicdesign/design_principles/emphasis_unity_tiles/emphasis_contrast_shape.jpg
Picture 2:
Is not just about Google-Alluring Visual Contrasts for Landing Page Conversions, (N.D) [Online Picture]. Retrieved from http://www.ivoryshorewebsite.com/wp-content/uploads/2011/06/Contrastofsize.png
Picture 3:
Darkness into Light, ( 9 April) [Online Picture]. Retrieved from http://fusionvocalensemble.files.wordpress.com/2011/07/tunnel1.jpg
Picture 4:
Ascender Fonts, (N.D) [Online Picture]. Retrieved from http://www.ascenderfonts.com/af/images/art/kat-tail-hmk-family-(2-fonts).png
Picture 5:
Ninaclock Design, (N.D) [Online Picture]. Retrieved from http://ninaclock.com/files/content/2007/ColourContrast.jpg