Info about the slider

Hi, i am trying to get the slider to show images with the same measure, cause it usually try to show images at their custom width and height.

Can anyone tell me which size images should be to look all the same and not having the slider to change measures with every image?

Also please i’d like a confirm about the way images get’s added to the slider, cause i usually add them with the ad media button and then in the setting i usually select path-slider-thumbnail 600×272 is that correct?

thanks already!