Question: Do Perl, Python or Ruby run flawless on a 64bit Win7 system, or do you have to keep in mind pitfalls with integers and restriction on functions like I have read of on PHP?

Answer: 
```
img#id {
    content:url(http://example.com/image.png);
}

```

this may be of use to you, define each of your images in the respective media queries.
you can't change an image source like that. You'll need to use a div with the original as a background image for this to work.

```
<div id="ifMobile1" style="background-image: url(images/arts/IMG_1447m.png);"></div>

```