colocando este script sobre main, y entrando al juego te da la opcion que al presionar f5 saques una screen que se guarda en la carpeta del juego

Script:

Código:

#==============================================================================
#  Screenshot
#  Version: 1.0
#  Author: modern algebra
#  Date: April 5, 2010
#++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
#  Description:
#    This script allows the player to take a screenshot of any area in the game
#  that he/she wants. Useful for sharing achievements I suppose.
#++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
#  Instructions:
#    All you need to do is set which button you want to use for taking
#  screenshots with at line 31, and set the destination folder for screenshots
#  at line 33.
#    If you want to force a screenshot, you can put this code in a call script:
#      $scene.take_screenshot
#==============================================================================
#==============================================================================
# ** Scene_Base
#++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
#  Summary of Changes:
#    new constant - MA_SCREENSHOT_BUTTON, MA_SCREENSHOT_PATH
#    aliased method - update
#==============================================================================

class Scene_Base
  #~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  # * CONSTANTS
  #~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  #  MA_SCREENSHOT_BUTTON - the button to press to take a Screenshot
  MA_SCREENSHOT_BUTTON = Input::F5
  #  MA_SCREENSHOT_PATH - the path to save the file
  MA_SCREENSHOT_PATH = "Screenshot "
  #~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  # * Frame Update
  #~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  alias modag_screenshot_upd_9ik2 update
  def update (*args)
    modag_screenshot_upd_9ik2 (*args) # Run Original Method
    if Input.trigger? (MA_SCREENSHOT_BUTTON)
      take_screenshot
    end
  end
  #~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  # * Take Screenshot
  #~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  def take_screenshot
    x = 1
    while FileTest.exist? ("#{MA_SCREENSHOT_PATH}#{x}.png")
      x += 1
    end
    Graphics.snap_to_bitmap.make_png (x.to_s, MA_SCREENSHOT_PATH, 1)
  end
end
#==============================================================================
#  Everything below this point is the PNG Saver script, written by 66rpg.com
#==============================================================================

# PNG Saver by 66rpg.com

module Zlib
  class Png_File < GzipWriter
    def make_png(bitmap, mode = 0)
      @bitmap, @mode = bitmap, mode
      self.write(make_header)
      self.write(make_ihdr)
      self.write(make_idat)
      self.write(make_iend)
    end
    def make_header
      return [0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a].pack('C*')
    end
    def make_ihdr
      ih_size              = [13].pack('N')
      ih_sign              = 'IHDR'
      ih_width              = [@bitmap.width].pack('N')
      ih_height            = [@bitmap.height].pack('N')
      ih_bit_depth          = [8].pack('C')
      ih_color_type        = [6].pack('C')
      ih_compression_method = [0].pack('C')
      ih_filter_method      = [0].pack('C')
      ih_interlace_method  = [0].pack('C')
      string = ih_sign + ih_width + ih_height + ih_bit_depth + ih_color_type +
              ih_compression_method + ih_filter_method + ih_interlace_method
      ih_crc = [Zlib.crc32(string)].pack('N')
      return ih_size + string + ih_crc
    end
    def make_idat
      header  = "\x49\x44\x41\x54"
      data    = @mode == 0 ? make_bitmap_data0 : make_bitmap_data1
      data    = Zlib::Deflate.deflate(data, 8)
      crc    = [Zlib.crc32(header + data)].pack('N')
      size    = [data.length].pack('N')
      return size + header + data + crc
    end
    def make_bitmap_data0
      gz = Zlib::GzipWriter.open('png2.tmp')
      t_Fx = 0
      w = @bitmap.width
      h = @bitmap.height
      data = []
      for y in 0...h
        data.push(0)
        for x in 0...w
          t_Fx += 1
          if t_Fx % 10000 == 0
            Graphics.update
            if t_Fx % 100000 == 0
              s = data.pack('C*')
              gz.write(s)
              data.clear
            end
          end
          color = @bitmap.get_pixel(x, y)
          data.push(color.red, color.green, color.blue, color.alpha)
        end
      end
      s = data.pack('C*')
      gz.write(s)
      gz.close 
      data.clear
      gz = Zlib::GzipReader.open('png2.tmp')
      data = gz.read
      gz.close
      File.delete('png2.tmp')
      return data
    end
    def make_bitmap_data1
      w = @bitmap.width
      h = @bitmap.height
      data = []
      for y in 0...h
        data.push(0)
        for x in 0...w
          color = @bitmap.get_pixel(x, y)
          data.push(color.red, color.green, color.blue, color.alpha)
        end
      end
      return data.pack('C*')
    end
    def make_iend
      ie_size = [0].pack('N')
      ie_sign = 'IEND'
      ie_crc  = [Zlib.crc32(ie_sign)].pack('N')
      return ie_size + ie_sign + ie_crc
    end
  end
end

#=============================================================================
# ** Bitmap
#=============================================================================
class Bitmap
  def make_png(name = 'like', path = '', mode = 0)
    Zlib::Png_File.open('png.tmp')  { |gz| gz.make_png(self, mode) }
    Zlib::GzipReader.open('png.tmp') { |gz| $read = gz.read }
    f = File.open(path + name + '.png', 'wb')
    f.write($read)
    f.close
    File.delete('png.tmp')
  end
end

creditos: modern algebra

Ah ..... Prefiero presionar alt+impr pero supongo que este tambien sirve... Lo probaré luego, gracias!