diff --git a/cricket.bmp b/cricket.bmp
new file mode 100644
index 0000000..7a504bd
Binary files /dev/null and b/cricket.bmp differ
diff --git a/seekablebitmap.py b/seekablebitmap.py
new file mode 100644
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--- /dev/null
+++ b/seekablebitmap.py
@@ -0,0 +1,140 @@
+# SPDX-FileCopyrightText: 2021 Jeff Epler for Adafruit Industries
+#
+# SPDX-License-Identifier: MIT
+
+import struct
+
+class SeekableBitmap:
+    """Allow random access to an uncompressed bitmap file on disk"""
+    def __init__(
+        self,
+        image_file,
+        width,
+        height,
+        bits_per_pixel,
+        *,
+        bytes_per_row=None,
+        data_start=None,
+        stride=None,
+        palette=None,
+    ):
+        """Construct a SeekableBitmap"""
+        self.image_file = image_file
+        self.width = width
+        self.height = height
+        self.bits_per_pixel = bits_per_pixel
+        self.bytes_per_row = (
+            bytes_per_row if bytes_per_row else (bits_per_pixel * width + 7) // 8
+        )
+        self.stride = stride if stride else self.bytes_per_row
+        self.palette = palette
+        self.data_start = data_start if data_start else image_file.tell()
+
+    def get_row(self, row):
+        self.image_file.seek(self.data_start + row * self.stride)
+        return self.image_file.read(self.bytes_per_row)
+
+
+def _pnmopen(filename):
+    """
+    Scan for netpbm format info, skip over comments, and read header data.
+
+    Return the format, header, and the opened file positioned at the start of
+    the bitmap data.
+    """
+    # pylint: disable=too-many-branches
+    image_file = open(filename, "rb")
+    magic_number = image_file.read(2)
+    image_file.seek(2)
+    pnm_header = []
+    next_value = bytearray()
+    while True:
+        # We have all we need at length 3 for formats P2, P3, P5, P6
+        if len(pnm_header) == 3:
+            return image_file, magic_number, pnm_header
+
+        if len(pnm_header) == 2 and magic_number in [b"P1", b"P4"]:
+            return image_file, magic_number, pnm_header
+
+        next_byte = image_file.read(1)
+        if next_byte == b"":
+            raise RuntimeError("Unsupported image format {}".format(magic_number))
+        if next_byte == b"#":  # comment found, seek until a newline or EOF is found
+            while image_file.read(1) not in [b"", b"\n"]:  # EOF or NL
+                pass
+        elif not next_byte.isdigit():  # boundary found in header data
+            if next_value:
+                # pull values until space is found
+                pnm_header.append(int("".join(["%c" % char for char in next_value])))
+                next_value = bytearray()  # reset the byte array
+        else:
+            next_value += next_byte  # push the digit into the byte array
+
+
+def pnmopen(filename):
+    """
+    Interpret netpbm format info and construct a SeekableBitmap
+    """
+    image_file, magic_number, pnm_header = _pnmopen(filename)
+    if magic_number == b"P4":
+        return SeekableBitmap(
+            image_file,
+            pnm_header[0],
+            pnm_header[1],
+            1,
+            palette=b"\xff\xff\xff\x00\x00\x00\x00\x00",
+        )
+    if magic_number == b"P5":
+        return SeekableBitmap(
+            image_file, pnm_header[0], pnm_header[1], pnm_header[2].bit_length()
+        )
+    if magic_number == b"P6":
+        return SeekableBitmap(
+            image_file, pnm_header[0], pnm_header[1], 3 * pnm_header[2].bit_length()
+        )
+    raise ValueError(f"Unknown or unsupported magic number {magic_number}")
+
+
+def bmpopen(filename):
+    """
+    Interpret bmp format info and construct a SeekableBitmap
+    """
+    image_file = open(filename, "rb")
+
+    header = image_file.read(34)
+
+    data_start, header_size, width, height, _, bits_per_pixel, _ = struct.unpack(
+        "<10x4l2hl", header
+    )
+
+    bits_per_pixel = bits_per_pixel if bits_per_pixel != 0 else 1
+
+    palette_start = header_size + 14
+    image_file.seek(palette_start)
+    palette = image_file.read(4 << bits_per_pixel)
+
+    stride = (bits_per_pixel * width + 31) // 32 * 4
+    if height < 0:
+        height = -height
+    else:
+        data_start = data_start + stride * (height - 1)
+        stride = -stride
+
+    return SeekableBitmap(
+        image_file,
+        width,
+        height,
+        bits_per_pixel,
+        data_start=data_start,
+        stride=stride,
+        palette=palette,
+    )
+
+
+def imageopen(filename):
+    """
+    Open a bmp or pnm file as a seekable bitmap
+    """
+    if filename.lower().endswith(".bmp"):
+        return bmpopen(filename)
+    return pnmopen(filename)