Header image positioned incorrectly on Firefox

Hi everyone,

Sorry I am a bit of a wordpress newbie here.

I have been customising the ‘Twenty Eleven’ theme offline using MAMP so hosting it on a local server. It’s all been going really well but I’ve hit one snag.

I customised the header.php file to include a banner image, but when I do, the image suddenly flips over to the right side. See this: https://i57.tinypic.com/2lw61xy.png – sorry I can’t link to the website as it’s only on my local server at the moment. In the picture you will see I have been trying to use MetaSlider (and weirdly, the arrows are correctly positioned), but it does the exact same thing when I use a plain old image too.

It only happens on Firefox and it does not do it when I don’t use an image (i.e. I wrote the words ‘test’ instead and it was positioned fine).

I’ve tried and tried to isolate the div layer but I just can’t work it out. I think I have found the div it’s contained in…. #branding… but nothing I change seems to make any difference, plus there is other content in that div layer which is positioned just fine. So I’m thinking it must be something else?

Sorry I’m not sure what other details to include but if anyone has any ideas what may be causing this issue, it’d be much appreciated!

Cheers