diff --git a/project/build.scala b/project/build.scala
index 1337898..3034720 100644
--- a/project/build.scala
+++ b/project/build.scala
@@ -56,6 +56,7 @@
       "org.apache.commons" % "commons-email" % "1.3.3",
       "org.apache.httpcomponents" % "httpclient" % "4.3.6",
       "org.apache.sshd" % "apache-sshd" % "0.11.0",
+      "org.apache.tika" % "tika-core" % "1.10",
       "com.typesafe.slick" %% "slick" % "2.1.0",
       "com.novell.ldap" % "jldap" % "2009-10-07",
       "com.h2database" % "h2" % "1.4.180",
diff --git a/src/main/scala/gitbucket/core/controller/FileUploadController.scala b/src/main/scala/gitbucket/core/controller/FileUploadController.scala
index c3503ac..d6213a2 100644
--- a/src/main/scala/gitbucket/core/controller/FileUploadController.scala
+++ b/src/main/scala/gitbucket/core/controller/FileUploadController.scala
@@ -17,22 +17,22 @@
   configureMultipartHandling(MultipartConfig(maxFileSize = Some(3 * 1024 * 1024)))
 
   post("/image"){
-    execute { (file, fileId) =>
+    execute({ (file, fileId) =>
       FileUtils.writeByteArrayToFile(new java.io.File(getTemporaryDir(session.getId), fileId), file.get)
       session += Keys.Session.Upload(fileId) -> file.name
-    }
+    }, FileUtil.isImage)
   }
 
-  post("/image/:owner/:repository"){
-    execute { (file, fileId) =>
+  post("/file/:owner/:repository"){
+    execute({ (file, fileId) =>
       FileUtils.writeByteArrayToFile(new java.io.File(
         getAttachedDir(params("owner"), params("repository")),
         fileId + "." + FileUtil.getExtension(file.getName)), file.get)
-    }
+    }, FileUtil.isUploadableType)
   }
 
-  private def execute(f: (FileItem, String) => Unit) = fileParams.get("file") match {
-    case Some(file) if(FileUtil.isImage(file.name)) =>
+  private def execute(f: (FileItem, String) => Unit, mimeTypeChcker: (String) => Boolean) = fileParams.get("file") match {
+    case Some(file) if(mimeTypeChcker(file.name)) =>
       defining(FileUtil.generateFileId){ fileId =>
         f(file, fileId)
 
diff --git a/src/main/scala/gitbucket/core/controller/IssuesController.scala b/src/main/scala/gitbucket/core/controller/IssuesController.scala
index b15cd16..21821a5 100644
--- a/src/main/scala/gitbucket/core/controller/IssuesController.scala
+++ b/src/main/scala/gitbucket/core/controller/IssuesController.scala
@@ -332,6 +332,7 @@
     (Directory.getAttachedDir(repository.owner, repository.name) match {
       case dir if(dir.exists && dir.isDirectory) =>
         dir.listFiles.find(_.getName.startsWith(params("file") + ".")).map { file =>
+          response.setHeader("Content-Disposition", f"""inline; filename=${file.getName}""")
           RawData(FileUtil.getMimeType(file.getName), file)
         }
       case _ => None
diff --git a/src/main/scala/gitbucket/core/util/FileUtil.scala b/src/main/scala/gitbucket/core/util/FileUtil.scala
index d3428fb..f753a60 100644
--- a/src/main/scala/gitbucket/core/util/FileUtil.scala
+++ b/src/main/scala/gitbucket/core/util/FileUtil.scala
@@ -1,7 +1,7 @@
 package gitbucket.core.util
 
 import org.apache.commons.io.FileUtils
-import java.net.URLConnection
+import org.apache.tika.Tika
 import java.io.File
 import ControlUtil._
 import scala.util.Random
@@ -9,8 +9,8 @@
 object FileUtil {
 
   def getMimeType(name: String): String =
-    defining(URLConnection.getFileNameMap()){ fileNameMap =>
-      fileNameMap.getContentTypeFor(name) match {
+    defining(new Tika()){ tika =>
+      tika.detect(name) match {
         case null     => "application/octet-stream"
         case mimeType => mimeType
       }
@@ -28,6 +28,8 @@
 
   def isImage(name: String): Boolean = getMimeType(name).startsWith("image/")
 
+  def isUploadableType(name: String): Boolean = mimeTypeWhiteList contains getMimeType(name)
+
   def isLarge(size: Long): Boolean = (size > 1024 * 1000)
 
   def isText(content: Array[Byte]): Boolean = !content.contains(0)
@@ -50,4 +52,14 @@
       FileUtils.deleteDirectory(dir)
     }
   }
+
+  val mimeTypeWhiteList: Array[String] = Array(
+      "application/pdf",
+      "application/vnd.openxmlformats-officedocument.presentationml.presentation",
+      "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet",
+      "application/vnd.openxmlformats-officedocument.wordprocessingml.document",
+      "image/gif",
+      "image/jpeg",
+      "image/png",
+      "text/plain")
 }
diff --git a/src/main/twirl/gitbucket/core/helper/attached.scala.html b/src/main/twirl/gitbucket/core/helper/attached.scala.html
index 33bd58e..0ceb228 100644
--- a/src/main/twirl/gitbucket/core/helper/attached.scala.html
+++ b/src/main/twirl/gitbucket/core/helper/attached.scala.html
@@ -1,22 +1,24 @@
 @(owner: String, repository: String)(textarea: Html)(implicit context: gitbucket.core.controller.Context)
 @import context._
+@import gitbucket.core.util.FileUtil
 <div class="muted attachable">
   @textarea
-  <div class="clickable">Attach images by dragging &amp; dropping, or selecting them.</div>
+  <div class="clickable">Attach images or documents by dragging &amp; dropping, or selecting them.</div>
 </div>
 @defining("(id=\")([\\w\\-]*)(\")".r.findFirstMatchIn(textarea.body).map(_.group(2))){ textareaId =>
 <script>
 $(function(){
   try {
     $([$('#@textareaId').closest('div')[0], $('#@textareaId').next('div')[0]]).dropzone({
-      url: '@path/upload/image/@owner/@repository',
+      url: '@path/upload/file/@owner/@repository',
       maxFilesize: 10,
-      acceptedFiles: 'image/*',
-      dictInvalidFileType: 'Unfortunately, we don\'t support that file type. Try again with a PNG, GIF, or JPG.',
-      previewTemplate: "<div class=\"dz-preview\">\n  <div class=\"dz-progress\"><span class=\"dz-upload\" data-dz-uploadprogress>Uploading your images...</span></div>\n  <div class=\"dz-error-message\"><span data-dz-errormessage></span></div>\n</div>",
+      acceptedFiles: @Html(FileUtil.mimeTypeWhiteList.mkString("'", ",", "'")),
+      dictInvalidFileType: 'Unfortunately, we don\'t support that file type. Try again with a PNG, GIF, JPG, DOCX, PPTX, XLSX, TXT, or PDF.',
+      previewTemplate: "<div class=\"dz-preview\">\n  <div class=\"dz-progress\"><span class=\"dz-upload\" data-dz-uploadprogress>Uploading your files...</span></div>\n  <div class=\"dz-error-message\"><span data-dz-errormessage></span></div>\n</div>",
       success: function(file, id) {
-        var images = '\n![' + file.name.split('.')[0] + '](@baseUrl/@owner/@repository/_attached/' + id + ')';
-        $('#@textareaId').val($('#@textareaId').val() + images);
+        var attachFile = (file.type.match(/image\/.*/) ? '\n![' + file.name.split('.')[0] : '\n[' + file.name) +
+          '](@baseUrl/@owner/@repository/_attached/' + id + ')';
+        $('#@textareaId').val($('#@textareaId').val() + attachFile);
         $(file.previewElement).prevAll('div.dz-preview').addBack().remove();
       }
     });