Here is an example image without text wrap. Note the tags
DISPLAY: block and
TEXT-ALIGN:center
This is an example with text wrap. Note the tag
FLOAT:left.
If you have images that are wrapped and you don't want them to be, just remove
FLOAT: left and add
DISPLAY: block; TEXT-ALIGN:center.
Disclaimer: I am not an HTML expert, but this is what works for me in Blogger. I hope this helps.