Here is an example of what carmenchu suggested. I also recommend you test on your specific platforms.
Two on same page:
I would move the <style> into a separate, linked, css sheet. The max-width should be set to your images - it is there to prevent small images from being over-blown and getting fuzzy.
The 'page-break-inside:avoid' isn't always respected by devices/apps...but it doesn't hurt to try...
Two on same page, side-by-side:
These settings can all be adjusted to suit your preferences. I hope that helps!