diff --git a/app/Http/Controllers/Apis/Protected/Summit/OAuth2PresentationApiController.php b/app/Http/Controllers/Apis/Protected/Summit/OAuth2PresentationApiController.php
index 001af3de..3ecbf285 100644
--- a/app/Http/Controllers/Apis/Protected/Summit/OAuth2PresentationApiController.php
+++ b/app/Http/Controllers/Apis/Protected/Summit/OAuth2PresentationApiController.php
@@ -14,6 +14,7 @@
 use App\Http\Utils\FileTypes;
 use App\Http\Utils\MultipartFormDataCleaner;
 use App\Models\Foundation\Main\IGroup;
+use Illuminate\Support\Facades\Config;
 use libs\utils\HTMLCleaner;
 use models\exceptions\EntityNotFoundException;
 use models\exceptions\ValidationException;
@@ -612,8 +613,9 @@ final class OAuth2PresentationApiController extends OAuth2ProtectedController
             $data = MultipartFormDataCleaner::cleanBool('featured', $data);
 
             $rules = [
-                'file'            => 'required_without:link',
-                'link'            => 'required_without:file|url',
+                'file'            => 'required_without_all:link,filepath',
+                'link'            => 'required_without_all:file,filepath|url',
+                'filepath'        => 'required_without_all:link,file',
                 'name'            => 'required|string:512',
                 'description'     => 'nullable|string',
                 'display_on_site' => 'nullable|boolean',
@@ -639,7 +641,8 @@ final class OAuth2PresentationApiController extends OAuth2ProtectedController
                 $request,
                 $presentation_id,
                 HTMLCleaner::cleanData($data, $fields),
-                array_merge(FileTypes::ImagesExntesions, FileTypes::SlidesExtensions)
+                array_merge(FileTypes::ImagesExntesions, FileTypes::SlidesExtensions),
+                intval(Config::get("mediaupload.slides_max_file_size"))
             );
 
             return $this->created(SerializerRegistry::getInstance()->getSerializer($slide)->serialize());
@@ -720,7 +723,8 @@ final class OAuth2PresentationApiController extends OAuth2ProtectedController
                 $presentation_id,
                 $slide_id,
                 HTMLCleaner::cleanData($data, $fields),
-                array_merge(FileTypes::ImagesExntesions, FileTypes::SlidesExtensions)
+                array_merge(FileTypes::ImagesExntesions, FileTypes::SlidesExtensions),
+                intval(Config::get("mediaupload.slides_max_file_size"))
             );
 
             return $this->updated(SerializerRegistry::getInstance()->getSerializer($slide)->serialize());
diff --git a/app/Http/Utils/FileSizeUtil.php b/app/Http/Utils/FileSizeUtil.php
new file mode 100644
index 00000000..f433a4e7
--- /dev/null
+++ b/app/Http/Utils/FileSizeUtil.php
@@ -0,0 +1,20 @@
+<?php namespace App\Http\Utils;
+/**
+ * Copyright 2020 OpenStack Foundation
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ **/
+
+final class FileSizeUtil
+{
+    public const Kb = 'KB';
+    public const MB = 'MB';
+    public const B = "Byte";
+}
\ No newline at end of file
diff --git a/app/Http/Utils/FileUploadInfo.php b/app/Http/Utils/FileUploadInfo.php
index cce7cd01..49f23d5a 100644
--- a/app/Http/Utils/FileUploadInfo.php
+++ b/app/Http/Utils/FileUploadInfo.php
@@ -23,8 +23,9 @@ use Illuminate\Http\UploadedFile;
  */
 final class FileUploadInfo
 {
+
     /**
-     * @var int
+     * @var int // in bytes
      */
     private $size;
     /**
@@ -80,7 +81,6 @@ final class FileUploadInfo
             $size = $file->getSize();
             if($size == 0)
                 throw new ValidationException("File size is zero.");
-            $size = $size/1024; // convert bytes to KB
             $fileName = $file->getClientOriginalName();
             $fileExt = pathinfo($fileName, PATHINFO_EXTENSION);
         }
@@ -97,7 +97,6 @@ final class FileUploadInfo
             if($size == 0)
                 throw new ValidationException("File size is zero.");
 
-            $size = $size/1024; // convert bytes to KB
             $fileName =  pathinfo($payload['filepath'],PATHINFO_BASENAME);
             $fileExt = pathinfo($fileName, PATHINFO_EXTENSION);
             $file = new UploadedFile($disk->path($payload['filepath']), $fileName);
@@ -111,13 +110,19 @@ final class FileUploadInfo
     }
 
     /**
-     * @return int
+     * @param string $unit
+     * @return int|null
      */
-    public function getSize(): ?int
+    public function getSize(string $unit = FileSizeUtil::Kb): ?int
     {
+        if($unit === FileSizeUtil::Kb){
+            return $this->size / 1024;
+        }
+
         return $this->size;
     }
 
+
     /**
      * @return UploadedFile
      */
diff --git a/app/Services/Model/IPresentationService.php b/app/Services/Model/IPresentationService.php
index fe9f6e10..a4ee99c7 100644
--- a/app/Services/Model/IPresentationService.php
+++ b/app/Services/Model/IPresentationService.php
@@ -107,7 +107,7 @@ interface IPresentationService
         $presentation_id,
         array $slide_data,
         array $allowed_extensions = [],
-        $max_file_size = 62914560
+        $max_file_size = 1048576 // bytes
     );
 
     /**
diff --git a/app/Services/Model/Imp/PresentationService.php b/app/Services/Model/Imp/PresentationService.php
index 5817f4c6..354e6b67 100644
--- a/app/Services/Model/Imp/PresentationService.php
+++ b/app/Services/Model/Imp/PresentationService.php
@@ -13,6 +13,7 @@
  **/
 use App\Events\PresentationMaterialDeleted;
 use App\Events\PresentationMaterialUpdated;
+use App\Http\Utils\FileSizeUtil;
 use App\Http\Utils\FileUploadInfo;
 use App\Http\Utils\IFileUploader;
 use App\Jobs\Emails\PresentationSubmissions\PresentationCreatorNotificationEmail;
@@ -690,7 +691,7 @@ final class PresentationService
         $presentation_id,
         array $slide_data,
         array $allowed_extensions =  [],
-        $max_file_size = 10485760
+        $max_file_size = 10485760 // bytes
     )
     {
         $slide = $this->tx_service->transaction(function () use (
@@ -710,30 +711,33 @@ final class PresentationService
                 throw new EntityNotFoundException('presentation not found!');
 
             $hasLink = isset($slide_data['link']) && !empty($slide_data['link']);
-            $hasFile = $request->hasFile('file');
+            $fileInfo = FileUploadInfo::build($request, $slide_data);
+            $hasFile = !is_null($fileInfo);
 
             if($hasFile && $hasLink){
                 throw new ValidationException("you must provide a file or a link, not both.");
             }
 
             $slide = PresentationSlideFactory::build($slide_data);
-
             // check if there is any file sent
             if($hasFile){
-                $file = $request->file('file');
-                if (!in_array($file->extension(), $allowed_extensions)) {
+
+                if (!in_array($fileInfo->getFileExt(), $allowed_extensions)) {
                     throw new ValidationException(
                         sprintf("file does not has a valid extension '(%s)'.", implode("','", $allowed_extensions)));
                 }
 
-                if ($file->getSize() > $max_file_size) {
+                if ($fileInfo->getSize(FileSizeUtil::B) > $max_file_size) {
                     throw new ValidationException(sprintf("file exceeds max_file_size (%s MB).", ($max_file_size / 1024) / 1024));
                 }
 
-                $slideFile = $this->file_uploader->build(
-                    $file,
+                $slideFile = $this->file_uploader->build
+                (
+                    $fileInfo->getFile(),
                     sprintf('summits/%s/presentations/%s/slides', $presentation->getSummitId(), $presentation_id),
-                    false);
+                    false
+                );
+
                 $slide->setSlide($slideFile);
             }
 
@@ -762,7 +766,7 @@ final class PresentationService
         $slide_id,
         array $slide_data,
         array $allowed_extensions = [],
-        $max_file_size = 10485760
+        $max_file_size = 10485760 // bytes
     ){
 
         $slide = $this->tx_service->transaction(function () use
@@ -793,7 +797,8 @@ final class PresentationService
 
 
             $hasLink = isset($slide_data['link']) && !empty($slide_data['link']);
-            $hasFile = $request->hasFile('file');
+            $fileInfo = FileUploadInfo::build($request, $slide_data);
+            $hasFile = !is_null($fileInfo);
 
             if($hasFile && $hasLink){
                 throw new ValidationException("you must provide a file or a link, not both.");
@@ -814,17 +819,22 @@ final class PresentationService
 
             // check if there is any file sent
             if($hasFile){
-                $file = $request->file('file');
-                if (!in_array($file->extension(), $allowed_extensions)) {
+                if (!in_array($fileInfo->getFileExt(), $allowed_extensions)) {
                     throw new ValidationException(
                         sprintf("file does not has a valid extension '(%s)'.", implode("','", $allowed_extensions)));
                 }
 
-                if ($file->getSize() > $max_file_size) {
+                if ($fileInfo->getSize(FileSizeUtil::B) > $max_file_size){
                     throw new ValidationException(sprintf("file exceeds max_file_size (%s MB).", ($max_file_size / 1024) / 1024));
                 }
 
-                $slideFile = $this->file_uploader->build($file, sprintf('summits/%s/presentations/%s/slides', $presentation->getSummitId(), $presentation_id), false);
+                $slideFile = $this->file_uploader->build
+                (
+                    $fileInfo->getFile(),
+                    sprintf('summits/%s/presentations/%s/slides', $presentation->getSummitId(), $presentation_id),
+                    false
+                );
+
                 $slide->setSlide($slideFile);
                 $slide->clearLink();
             }
diff --git a/config/mediaupload.php b/config/mediaupload.php
index 457464be..aeeabbc4 100644
--- a/config/mediaupload.php
+++ b/config/mediaupload.php
@@ -13,6 +13,7 @@
  **/
 
 return  [
-    // in MB
+    // in Bytes
+    'slides_max_file_size' => env('MEDIA_UPLOAD_SLIDES_MAX_FILE_SIZE', 524288000),
     'mounting_folder' => env('MEDIA_UPLOAD_MOUNTING_FOLDER','PresentationMediaUploads')
 ];