diff --git a/matemat/webserver/pagelets/admin.py b/matemat/webserver/pagelets/admin.py
index d1866b2..0095b67 100644
--- a/matemat/webserver/pagelets/admin.py
+++ b/matemat/webserver/pagelets/admin.py
@@ -2,6 +2,8 @@ from typing import Any, Dict, Union
 
 import os
 import magic
+from io import BytesIO
+from PIL import Image
 
 from matemat.webserver import pagelet, RequestArguments, PageletResponse, RedirectResponse, TemplateResponse
 from matemat.db import MatematDatabase
@@ -124,16 +126,20 @@ def handle_change(args: RequestArguments, user: User, db: MatematDatabase, confi
                 return
             # Detect the MIME type
             filemagic: magic.FileMagic = magic.detect_from_content(avatar)
-            # Currently, only image/png is supported, don't process any other formats
-            if filemagic.mime_type != 'image/png':
-                # TODO: Optionally convert to png
+            if not filemagic.mime_type.startswith('image/'):
                 return
             # Create the absolute path of the upload directory
             abspath: str = os.path.join(os.path.abspath(config['UploadDir']), 'thumbnails/users/')
             os.makedirs(abspath, exist_ok=True)
-            # Write the image to the file
-            with open(os.path.join(abspath, f'{user.id}.png'), 'wb') as f:
-                f.write(avatar)
+            try:
+                # Parse the image data
+                image: Image = Image.open(BytesIO(avatar))
+                # Resize the image to 150x150
+                image.thumbnail((150, 150), Image.LANCZOS)
+                # Write the image to the file
+                image.save(os.path.join(abspath, f'{user.id}.png'), 'PNG')
+            except OSError:
+                return
 
     except UnicodeDecodeError:
         raise ValueError('an argument not a string')
@@ -182,22 +188,26 @@ def handle_admin_change(args: RequestArguments, db: MatematDatabase, config: Dic
             # If a new product image was uploaded, process it
             if 'image' in args:
                 # Read the raw image data from the request
-                image = bytes(args.image)
+                avatar = bytes(args.image)
                 # Only process the image, if its size is more than zero.  Zero size means no new image was uploaded
-                if len(image) == 0:
+                if len(avatar) == 0:
                     return
                 # Detect the MIME type
-                filemagic: magic.FileMagic = magic.detect_from_content(image)
-                # Currently, only image/png is supported, don't process any other formats
-                if filemagic.mime_type != 'image/png':
-                    # TODO: Optionally convert to png
+                filemagic: magic.FileMagic = magic.detect_from_content(avatar)
+                if not filemagic.mime_type.startswith('image/'):
                     return
                 # Create the absolute path of the upload directory
                 abspath: str = os.path.join(os.path.abspath(config['UploadDir']), 'thumbnails/products/')
                 os.makedirs(abspath, exist_ok=True)
-                # Write the image to the file
-                with open(os.path.join(abspath, f'{newproduct.id}.png'), 'wb') as f:
-                    f.write(image)
+                try:
+                    # Parse the image data
+                    image: Image = Image.open(BytesIO(avatar))
+                    # Resize the image to 150x150
+                    image.thumbnail((150, 150), Image.LANCZOS)
+                    # Write the image to the file
+                    image.save(os.path.join(abspath, f'{newproduct.id}.png'), 'PNG')
+                except OSError:
+                    return
 
         # The user requested to restock a product
         elif change == 'restock':
diff --git a/matemat/webserver/pagelets/modproduct.py b/matemat/webserver/pagelets/modproduct.py
index ef6acbd..7ba9c3e 100644
--- a/matemat/webserver/pagelets/modproduct.py
+++ b/matemat/webserver/pagelets/modproduct.py
@@ -2,6 +2,8 @@ from typing import Any, Dict, Union
 
 import os
 import magic
+from PIL import Image
+from io import BytesIO
 
 from matemat.webserver import pagelet, RequestArguments, PageletResponse, RedirectResponse, TemplateResponse
 from matemat.db import MatematDatabase
@@ -101,19 +103,23 @@ def handle_change(args: RequestArguments, product: Product, db: MatematDatabase,
         # If a new product image was uploaded, process it
         if 'image' in args:
             # Read the raw image data from the request
-            image = bytes(args.image)
+            avatar = bytes(args.image)
             # Only process the image, if its size is more than zero.  Zero size means no new image was uploaded
-            if len(image) == 0:
+            if len(avatar) == 0:
                 return
             # Detect the MIME type
-            filemagic: magic.FileMagic = magic.detect_from_content(image)
-            # Currently, only image/png is supported, don't process any other formats
-            if filemagic.mime_type != 'image/png':
-                # TODO: Optionally convert to png
+            filemagic: magic.FileMagic = magic.detect_from_content(avatar)
+            if not filemagic.mime_type.startswith('image/'):
                 return
             # Create the absolute path of the upload directory
             abspath: str = os.path.join(os.path.abspath(config['UploadDir']), 'thumbnails/products/')
             os.makedirs(abspath, exist_ok=True)
-            # Write the image to the file
-            with open(os.path.join(abspath, f'{product.id}.png'), 'wb') as f:
-                f.write(image)
+            try:
+                # Parse the image data
+                image: Image = Image.open(BytesIO(avatar))
+                # Resize the image to 150x150
+                image.thumbnail((150, 150), Image.LANCZOS)
+                # Write the image to the file
+                image.save(os.path.join(abspath, f'{product.id}.png'), 'PNG')
+            except OSError:
+                return
diff --git a/matemat/webserver/pagelets/moduser.py b/matemat/webserver/pagelets/moduser.py
index 8be086c..94bfa84 100644
--- a/matemat/webserver/pagelets/moduser.py
+++ b/matemat/webserver/pagelets/moduser.py
@@ -2,6 +2,8 @@ from typing import Any, Dict, Optional, Union
 
 import os
 import magic
+from PIL import Image
+from io import BytesIO
 
 from matemat.webserver import pagelet, RequestArguments, PageletResponse, RedirectResponse, TemplateResponse
 from matemat.db import MatematDatabase
@@ -130,13 +132,17 @@ def handle_change(args: RequestArguments, user: User, authuser: User, db: Matema
                 return
             # Detect the MIME type
             filemagic: magic.FileMagic = magic.detect_from_content(avatar)
-            # Currently, only image/png is supported, don't process any other formats
-            if filemagic.mime_type != 'image/png':
-                # TODO: Optionally convert to png
+            if not filemagic.mime_type.startswith('image/'):
                 return
             # Create the absolute path of the upload directory
             abspath: str = os.path.join(os.path.abspath(config['UploadDir']), 'thumbnails/users/')
             os.makedirs(abspath, exist_ok=True)
-            # Write the image to the file
-            with open(os.path.join(abspath, f'{user.id}.png'), 'wb') as f:
-                f.write(avatar)
+            try:
+                # Parse the image data
+                image: Image = Image.open(BytesIO(avatar))
+                # Resize the image to 150x150
+                image.thumbnail((150, 150), Image.LANCZOS)
+                # Write the image to the file
+                image.save(os.path.join(abspath, f'{user.id}.png'), 'PNG')
+            except OSError:
+                return
diff --git a/templates/admin_all.html b/templates/admin_all.html
index b637cc7..d1aa1f2 100644
--- a/templates/admin_all.html
+++ b/templates/admin_all.html
@@ -34,7 +34,7 @@
         <img src="/upload/thumbnails/users/{{ authuser.id }}.png" alt="Avatar of {{ authuser.name }}" /><br/>
 
         <label for="admin-avatar-avatar">Upload new file: </label>
-        <input id="admin-avatar-avatar" type="file" name="avatar" accept="image/png" /><br/>
+        <input id="admin-avatar-avatar" type="file" name="avatar" accept="image/*" /><br/>
 
         <input type="submit" value="Save changes" />
     </form>
diff --git a/templates/admin_restricted.html b/templates/admin_restricted.html
index 36152c3..6b85a63 100644
--- a/templates/admin_restricted.html
+++ b/templates/admin_restricted.html
@@ -50,7 +50,7 @@
         <input id="admin-newproduct-price-non-member" type="number" min="0" name="pricenonmember" /><br/>
 
         <label for="admin-newproduct-image">Image: </label>
-        <input id="admin-newproduct-image" type="file" accept="image/png" /><br/>
+        <input id="admin-newproduct-image" type="file" accept="image/*" /><br/>
 
         <input type="submit" value="Create Product" />
     </form>
diff --git a/templates/modproduct.html b/templates/modproduct.html
index 2158139..338df82 100644
--- a/templates/modproduct.html
+++ b/templates/modproduct.html
@@ -26,7 +26,7 @@
         <label for="modproduct-image">
             <img height="150" src="/upload/thumbnails/products/{{ product.id }}.png" alt="Image of {{ product.name }}" />
         </label><br/>
-        <input id="modproduct-image" type="file" name="image" accept="image/png" /><br/>
+        <input id="modproduct-image" type="file" name="image" accept="image/*" /><br/>
 
         <input id="modproduct-productid" type="hidden" name="productid" value="{{ product.id }}" /><br/>
 
diff --git a/templates/moduser.html b/templates/moduser.html
index 894d198..e40e393 100644
--- a/templates/moduser.html
+++ b/templates/moduser.html
@@ -44,7 +44,7 @@
         <label for="moduser-account-avatar">
             <img height="150" src="/upload/thumbnails/users/{{ user.id }}.png" alt="Avatar of {{ user.name }}" />
         </label><br/>
-        <input id="moduser-account-avatar" type="file" name="avatar" accept="image/png" /><br/>
+        <input id="moduser-account-avatar" type="file" name="avatar" accept="image/*" /><br/>
 
         <input id="moduser-account-userid" type="hidden" name="userid" value="{{ user.id }}" /><br/>