CSS Media Query Not Working in FF

I have a media query set in my CSS to change an image on a page if a max-width of 450px is crossed.  It works in all browsers but does something strange in FF.  It changes the image if you go smaller than 1350 px in width.  It should not change until the browser width is 450px or small.

Any ideas?
Who is Participating?

[Product update] Infrastructure Analysis Tool is now available with Business Accounts.Learn More

I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

Marco GasiFreelancerCommented:
In ffx 40.0.3 I have following steps:
1040px - 688px - 488px
Thi for different map sizes (from 1920px downto 1040px width the map gracefully reduces its size then there is a sudden change, then the image is responsive again downto 688px: here another sudden change, then reponsive resizing downto 488px).
But if the change you're talking about is that because of in the image appear three blue zone with three white labels with rounded corners, then this happens at 460px or so.

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
Marco GasiFreelancerCommented:
Thank you for the point, but... what is the solution? I'm just curious :-)
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today

From novice to tech pro — start learning today.