diff --git a/common/pnm.c b/common/pnm.c
new file mode 100644
index 0000000..fe77dde
--- /dev/null
+++ b/common/pnm.c
@@ -0,0 +1,154 @@
+/* Copyright (C) 2013-2016, The Regents of The University of Michigan.
+All rights reserved.
+This software was developed in the APRIL Robotics Lab under the
+direction of Edwin Olson, ebolson@umich.edu. This software may be
+available under alternative licensing terms; contact the address above.
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+1. Redistributions of source code must retain the above copyright notice, this
+   list of conditions and the following disclaimer.
+2. Redistributions in binary form must reproduce the above copyright notice,
+   this list of conditions and the following disclaimer in the documentation
+   and/or other materials provided with the distribution.
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
+ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+The views and conclusions contained in the software and documentation are those
+of the authors and should not be interpreted as representing official policies,
+either expressed or implied, of the Regents of The University of Michigan.
+*/
+
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "pnm.h"
+
+pnm_t *pnm_create_from_file(const char *path)
+{
+    FILE *f = fopen(path, "rb");
+    if (f == NULL)
+        return NULL;
+
+    pnm_t *pnm = calloc(1, sizeof(pnm_t));
+    pnm->format = -1;
+
+    char tmp[1024];
+    int nparams = 0; // will be 3 when we're all done.
+    int params[3];
+
+    while (nparams < 3 && !(pnm->format == PNM_FORMAT_BINARY && nparams == 2)) {
+        if (fgets(tmp, sizeof(tmp), f) == NULL)
+            goto error;
+
+        // skip comments
+        if (tmp[0]=='#')
+            continue;
+
+        char *p = tmp;
+
+        if (pnm->format == -1 && tmp[0]=='P') {
+            pnm->format = tmp[1]-'0';
+            assert(pnm->format == PNM_FORMAT_GRAY || pnm->format == PNM_FORMAT_RGB || pnm->format == PNM_FORMAT_BINARY);
+            p = &tmp[2];
+        }
+
+        // pull integers out of this line until there are no more.
+        while (nparams < 3 && *p!=0) {
+            while (*p==' ')
+                p++;
+
+            // encounter rubbish? (End of line?)
+            if (*p < '0' || *p > '9')
+                break;
+
+            int acc = 0;
+            while (*p >= '0' && *p <= '9') {
+                acc = acc*10 + *p - '0';
+                p++;
+            }
+
+            params[nparams++] = acc;
+            p++;
+        }
+    }
+
+    pnm->width = params[0];
+    pnm->height = params[1];
+    pnm->max = params[2];
+
+    switch (pnm->format) {
+        case PNM_FORMAT_BINARY: {
+            // files in the wild sometimes simply don't set max
+            pnm->max = 1;
+
+            pnm->buflen = pnm->height * ((pnm->width + 7)  / 8);
+            pnm->buf = malloc(pnm->buflen);
+            size_t len = fread(pnm->buf, 1, pnm->buflen, f);
+            if (len != pnm->buflen)
+                goto error;
+
+            fclose(f);
+            return pnm;
+        }
+
+        case PNM_FORMAT_GRAY: {
+            if (pnm->max == 255)
+                pnm->buflen = pnm->width * pnm->height;
+            else if (pnm->max == 65535)
+                pnm->buflen = 2 * pnm->width * pnm->height;
+            else
+                assert(0);
+
+            pnm->buf = malloc(pnm->buflen);
+            size_t len = fread(pnm->buf, 1, pnm->buflen, f);
+            if (len != pnm->buflen)
+                goto error;
+
+            fclose(f);
+            return pnm;
+        }
+
+        case PNM_FORMAT_RGB: {
+            if (pnm->max == 255)
+                pnm->buflen = pnm->width * pnm->height * 3;
+            else if (pnm->max == 65535)
+                pnm->buflen = 2 * pnm->width * pnm->height * 3;
+            else
+                assert(0);
+
+            pnm->buf = malloc(pnm->buflen);
+            size_t len = fread(pnm->buf, 1, pnm->buflen, f);
+            if (len != pnm->buflen)
+                goto error;
+            fclose(f);
+            return pnm;
+        }
+    }
+
+error:
+    fclose(f);
+
+    if (pnm != NULL) {
+        free(pnm->buf);
+        free(pnm);
+    }
+
+    return NULL;
+}
+
+void pnm_destroy(pnm_t *pnm)
+{
+    if (pnm == NULL)
+        return;
+
+    free(pnm->buf);
+    free(pnm);
+}