Hi ptityop,

The image slider is based on ResponsiveSlides.js, which does not have swipe support. Adding swipe to it might be a lot of work.
https://github.com/viljamis/ResponsiveSlides.js...

There is a free image slider in the marketplace that is touch friendly. You can test it to see if it accepts swipes.
http://www.concrete5.org/marketplace/addons/simple-slider...

Another option is creating a custom block template for the image slider.You would use a JavaScript image slider script that does support swipe. FlexSlider is listed as having swipe support.
http://www.woothemes.com/flexslider/...

There is a video of Andrew customizing the image slider.
http://www.concrete5.org/documentation/developers/5.7/working-with-...

I am guessing you are using the 5.7 built in image slider.

Not a solution for 5.7, but for anyone using 5.6 and a slider addon, you can swipe enable it using my 'Instant Swipe' block.
http://www.concrete5.org/marketplace/addons/instant-swipe/...