Zip the file, then in a reply post Insert>>Image/video/file>>click Upload>>browse for file>>OK.
Or upload the fit file to a reputable file sharing service, such as OneDrive, Google Drive, Dropbox, make the file public, then paste a link to the file in your post.
Some suggestions to help minimize the occurrence of corrupt fit files on a Forerunner 25.
Avoid pressing stop or pause during an activity.
Sync your watch, backup the \GARMIN\ACTIVITY folder, then do a full master reset of your Forerunner 25 using these directions - Forerunner 25 - Clearing User Data.
Perform a weekly cleanup of the \GARMIN\ACTIVITY folder using these directions - Removing Recorded Activities to Free Up Space. The F25 seems to have problems with longer activities, so this step is important before a longer event.
