i have an article driven from a db and it contains image tag, i need a regex to grab that image and put it into anchor tags

i have an article driven from a db and it contains image tag, i need a
regex to grab that image and put it into anchor tags

Some text before <img style="float: left;"
src="../images/265218_imgthw.jpg" alt="" width="81" height="88"> some text
after
Say i have something like that wrap inside some text coming from db. I
need it to be changed to:
Some text before <a href='../images/265218_imgthw.jpg'><img style="float:
left;" src="../images/265218_imgthw.jpg" alt="" width="81"
height="88"></a> some text after
Any help please.