how active ImageMagick on windows 8?

I have installed Omeka 2.3 (not 2.3.1) on Windows 8.1 but I have a problem with imagemagick despite having installed and assigned the path configurations, Omeka not generate thumbnails. I have installed ImageMagick-6.8.9-Q16

Thanks for your help!

Have you tried using the GD Image Creation option?

No yet I'll try... thanks