EXPR: 
  EXPR + EXPR
  EXPR - EXPR
  - EXPR
  + EXPR
  ! EXPR
  ( EXPR )
  EXPR == EXPR
  EXPR != EXPR
  EXPR <= EXPR
  EXPR >= EXPR
  EXPR < EXPR
  EXPR > EXPR
  NUMBER
  RVAR

NUMBER:
  unsigned integer number

RVAR (Readable Variables):	
  images
  image_idx
  pages
  page_idx

WVAR (Writable Variables):
  thumbnail_width
  thumbnail_height

---

<gthumb:title/>

<gthumb:image/>
  idx=EXPR
  idx_relative=EXPR
  thumbnail="0/1"
  max_size=EXPR
  border=EXPR

<gthumb:image_link/>
  idx=EXPR
  idx_relative=EXPR
  thumbnail="0/1"

<gthumb:image_idx/>
  idx_relative=EXPR

<gthumb:image_dim/>
  idx=EXPR
  idx_relative=EXPR

<gthumb:images/>

<gthumb:file_name/>
  idx=EXPR
  idx_relative=EXPR
  with_path="0/1"
  with_relative_path="0/1"

<gthumb:file_path/>
  idx=EXPR
  idx_relative=EXPR
  relative_path="0/1"

<gthumb:file_size/>
  idx=EXPR
  idx_relative=EXPR

<gthumb:comment/>
  idx=EXPR
  idx_relative=EXPR
  max_size=EXPR

<gthumb:page_link/>
  idx=EXPR
  idx_relative=EXPR
  image_idx="0/1"

<gthumb:page_idx/>
  idx_relative=EXPR

<gthumb:pages/>

<gthumb:table/>

<gthumb:date/>

<gthumb:set_var WVAR=EXPR WVAR=EXPR [..] />

---

<gthumb:if EXPR/> 
 [HTML]
<gthumb:else_if EXPR/> 
 [HTML]
<gthumb:else_if EXPR/> 
 [HTML]
.
.
.
<gthumb:else_if EXPR/> 
 [HTML]
<gthumb:else/> 
 [HTML]
<gthumb:end/>
