I have a field named planextra2 whihc is a general comments field. When somebody uploads a picture using my program it will enter the comments 'Img Submit'. But the same comments field is allowed for users to add other information. Therefore I have a problem.

If the comments field is empty:

a) If the field is empty then the comments will be shown as 'Img Submit'
b) If the field has the value of 'Img Submit' then I want to replace it with 'Img Re-Submit'

If the comments field has comments in already then I need to somehow scan the field to see if 'Img Submit' or 'Img Re-Submit' is there. If its not there then append 'Img Submit'. If 'Img Submit' is there then replace 'Img Submit' with 'Img Re-submit'. For example:

Updated yesterday. Img Submit. Colours Red or Black

I would like this to be changed to:

Updated yesterday. Img Re-Submit. Colours Red or Black

I basically dont know how to scan the field and differentiate the comments I have added from the comments they might add.

Can anybody help me please