Featured Blog Post Image Size

We're trying to figure out the best size for the blog post images we want to feature in the slide show. Tried images sizes ranging from 300px wide to 1000px they all seem to stretch. Any help would be great!

 

Optical size of image in blog post is 640px wide and 340px height.

 

Hello,

I tried this, but it's still not working. Please help. My site is: http://www.harvardhispanic.org/

Also, what is the ideal size of the logo?

Thank you.

 

1. For your first issue, make the size of image 240px wide and 340px height.

2. For your second issue, make the size logo 230px wide and 90px height.