Images not wrapping/padding in new theme

I recently added a new theme to my wordpress blog and have found all my images aren’t wrapping properly, in all my posts I had used <div style=”float: left; margin: 0px;”> to make some padding and float to the left but it doesn’t seem to work in this new theme, is there anything I can change to make the images have a space when wrapped around the text? This is the single post css for the theme:

.post_meta { color: #666; padding: 0.3em 0 1.4em 0; }
.post_meta_tag { color: #666; }
.img { padding: 4px; margin: 0 7px 2px 0; display: inline; }
.post_meta p img { margin: 0; padding: 0; float: none; }
.post_meta p { margin: 0 0 0.4em 0; }
#post_content blockquote { float: left; width: 260px; color: #666; margin: 0 0 0 1em; color: #000; font: bold 1em georgia, serif; font-style: italic; letter-spacing: -0.048em; }
blockquote { margin: 13px 0; padding: 0 20px 0 50px; color: #333; background: url(‘images/bg/blockquote.gif’) no-repeat 10px 0; border: none; }
#post_content blockquote p { text-align: left; line-height: 1.7em; }
#post_content p img { margin: 0;padding:0; }
#post_content img.WP-PrintIcon, #post_content img.WP-EmailIcon, #post_content img.posttag { margin: 0 0.3em 0 0;padding: 0.1em 0 0 0; }
#post_content p a, #arch_content p a { color: #224970; }
#post_content p a:hover, #arch_content p a:hover { color: #000; text-decoration: underline; }