css float help

Hi,

My question is a little generic rather than theme specific so hoping someone can help me.

I want to use thumbnails in my posts and have the text wrap around them using css floats. The issue I am having is I can make something float either left or right but I can’t figure out what I need to do to get them to float whichever I choose by choosing image align property in the standard wordpress editor.

In other words, in one paragraph I am aligning the picture to the left and want to ‘float: left;’ and in the next i want to align the picture to the right and then ‘float: right;’

right now I find I can edit css and put in something like

img {
    float: left;
}

That works great until I want to align right. Hope I am explaining it good enough and hope someone can help ??

Thank you in advance