Required parameter - 

• image (picture file name with RELATIVE path)

Optional parameters -

• caption (Caption for under picture, no quotation marks)
• fg (Foreground color in 6-digit hexadecimal, defaults to black)
• bg (Background color in 6-digit hexadecimal, defaults to white)
• lnk (link color in 6-digit hexadecimal, defaults to bright blue)
• vlnk (visited link color in 6-digit hexadecimal, defaults to purple)
• font (Font face as a string, no quotations, defaults to Arial, helvetica, sans-serif)
• size (Font size as an integer, optionally signed)
• backlabel (Show this string with href to referring url)
• nexturl (Show "Next" and reference specified RELATIVE url)
• doneurl (Show "Done" with href to specified RELATIVE url)

Example (white text on black background):

showpic.pl?image=subdir/mypic.jpg&caption=A picture of me.&fg=000000&bg=FFFFFF&font=times new roman&size=2&back=Back