Help With String Fuctions In Java

[Distortion]

I want to make a program that does the following online.converthttp://www.hereihostmyimages.com/folder/picture001.jpgto[img ]http://www.hereihostmyimages.com/folder/picture001.jpg[/img ][img ]http://www.hereihostmyimages.com/folder/picture002.jpg[/img ][img ]http://www.hereihostmyimages.com/folder/picture003.jpg[/img ]etcetera etcetera...I made something allready but it isn't as userfriendly as I wanted to. now it needs http://www.hereihostmyimages.com/folder/picture to be input in one textfield, the amount of tags in another textfield and the extension in a third textfield. What i want to do is detect the first '1' in the link. And cut the string into 2 at that point. Then with a loop replace the 01 with 02,03,04 and so on, and paste the extension at the end again.I've been looking at indexOf and others but I can't get it to work. Can someone tell me what functions to use here?Thanks in advance!