Test images for optimize
Without a doubt, the quality of compress depends from content of picture. For this reason, in my testing I`ll use 3 images: nature, city and face.
1 – Nature (376 Kb). Just field with sunflowers, because it like Ukrainian flag.
2 – City (300 Kb). Photo of nighty Kyiv, because it just beautiful city.
3 – Face (86 kb). Jana Zinkevich, known Volunteer.