<p>ファイル名のドット以下の文字を「拡張子」といい、通常は3文字、たまに4文字が使われます。画像ファイルのJPEGは3文字だとjpg、4文字だとjpeg。HTMLファイルは3文字だとhtm、4文字だとhtmlになっています。<&sol;p>&NewLine;<p>Windows以前のMS-DOSでは必ず拡張子がついていました。テキストベースだったので拡張子を見れば何のファイルかすぐわかるので便利だったわけですね。Windowsになってからデフォルトでは拡張子が表示されないようになっています。 デスクトップにファイルを配置した時に、何のファイルか判断するために拡張子がついていたほうがわかりやすいと思うのですが、どうでしょうか？<&sol;p>&NewLine;<h3>拡張子を表示するためには<&sol;h3>&NewLine;<p>コントロールパネルを開く<&sol;p>&NewLine;<p><a href&equals;"https&colon;&sol;&sol;bacque&period;biz&sol;wp-content&sol;uploads&sol;2014&sol;07&sol;20140711&lowbar;folderoption&lowbar;0&period;jpg"><img data-attachment-id&equals;"2244" data-permalink&equals;"https&colon;&sol;&sol;bacque&period;biz&sol;archives&sol;2231&sol;20140711&lowbar;folderoption&lowbar;0" data-orig-file&equals;"https&colon;&sol;&sol;i0&period;wp&period;com&sol;bacque&period;biz&sol;wp-content&sol;uploads&sol;2014&sol;07&sol;20140711&lowbar;folderoption&lowbar;0&period;jpg&quest;fit&equals;790&percnt;2C698&amp&semi;ssl&equals;1" data-orig-size&equals;"790&comma;698" data-comments-opened&equals;"1" data-image-meta&equals;"&lbrace;&quot&semi;aperture&quot&semi;&colon;&quot&semi;0&quot&semi;&comma;&quot&semi;credit&quot&semi;&colon;&quot&semi;&quot&semi;&comma;&quot&semi;camera&quot&semi;&colon;&quot&semi;&quot&semi;&comma;&quot&semi;caption&quot&semi;&colon;&quot&semi;&quot&semi;&comma;&quot&semi;created&lowbar;timestamp&quot&semi;&colon;&quot&semi;0&quot&semi;&comma;&quot&semi;copyright&quot&semi;&colon;&quot&semi;&quot&semi;&comma;&quot&semi;focal&lowbar;length&quot&semi;&colon;&quot&semi;0&quot&semi;&comma;&quot&semi;iso&quot&semi;&colon;&quot&semi;0&quot&semi;&comma;&quot&semi;shutter&lowbar;speed&quot&semi;&colon;&quot&semi;0&quot&semi;&comma;&quot&semi;title&quot&semi;&colon;&quot&semi;&quot&semi;&rcub;" data-image-title&equals;"20140711&lowbar;folderoption&lowbar;0" data-image-description&equals;"" data-image-caption&equals;"" data-medium-file&equals;"https&colon;&sol;&sol;i0&period;wp&period;com&sol;bacque&period;biz&sol;wp-content&sol;uploads&sol;2014&sol;07&sol;20140711&lowbar;folderoption&lowbar;0&period;jpg&quest;fit&equals;400&percnt;2C353&amp&semi;ssl&equals;1" data-large-file&equals;"https&colon;&sol;&sol;i0&period;wp&period;com&sol;bacque&period;biz&sol;wp-content&sol;uploads&sol;2014&sol;07&sol;20140711&lowbar;folderoption&lowbar;0&period;jpg&quest;fit&equals;660&percnt;2C583&amp&semi;ssl&equals;1" class&equals;"alignnone size-medium wp-image-2244" src&equals;"https&colon;&sol;&sol;bacque&period;biz&sol;wp-content&sol;uploads&sol;2014&sol;07&sol;20140711&lowbar;folderoption&lowbar;0-400x353&period;jpg" alt&equals;"20140711&lowbar;folderoption&lowbar;0" width&equals;"400" height&equals;"353" &sol;><&sol;a><&sol;p>&NewLine;<p>右上の「表示方法」をカテゴリから、小さいアイコンもしくは大きいアイコンに変更<&sol;p>&NewLine;<p><a href&equals;"https&colon;&sol;&sol;bacque&period;biz&sol;wp-content&sol;uploads&sol;2014&sol;07&sol;20140711&lowbar;folderoption&lowbar;1&period;jpg"><img data-attachment-id&equals;"2245" data-permalink&equals;"https&colon;&sol;&sol;bacque&period;biz&sol;archives&sol;2231&sol;20140711&lowbar;folderoption&lowbar;1" data-orig-file&equals;"https&colon;&sol;&sol;i0&period;wp&period;com&sol;bacque&period;biz&sol;wp-content&sol;uploads&sol;2014&sol;07&sol;20140711&lowbar;folderoption&lowbar;1&period;jpg&quest;fit&equals;833&percnt;2C768&amp&semi;ssl&equals;1" data-orig-size&equals;"833&comma;768" data-comments-opened&equals;"1" data-image-meta&equals;"&lbrace;&quot&semi;aperture&quot&semi;&colon;&quot&semi;0&quot&semi;&comma;&quot&semi;credit&quot&semi;&colon;&quot&semi;&quot&semi;&comma;&quot&semi;camera&quot&semi;&colon;&quot&semi;&quot&semi;&comma;&quot&semi;caption&quot&semi;&colon;&quot&semi;&quot&semi;&comma;&quot&semi;created&lowbar;timestamp&quot&semi;&colon;&quot&semi;0&quot&semi;&comma;&quot&semi;copyright&quot&semi;&colon;&quot&semi;&quot&semi;&comma;&quot&semi;focal&lowbar;length&quot&semi;&colon;&quot&semi;0&quot&semi;&comma;&quot&semi;iso&quot&semi;&colon;&quot&semi;0&quot&semi;&comma;&quot&semi;shutter&lowbar;speed&quot&semi;&colon;&quot&semi;0&quot&semi;&comma;&quot&semi;title&quot&semi;&colon;&quot&semi;&quot&semi;&rcub;" data-image-title&equals;"20140711&lowbar;folderoption&lowbar;1" data-image-description&equals;"" data-image-caption&equals;"" data-medium-file&equals;"https&colon;&sol;&sol;i0&period;wp&period;com&sol;bacque&period;biz&sol;wp-content&sol;uploads&sol;2014&sol;07&sol;20140711&lowbar;folderoption&lowbar;1&period;jpg&quest;fit&equals;400&percnt;2C368&amp&semi;ssl&equals;1" data-large-file&equals;"https&colon;&sol;&sol;i0&period;wp&period;com&sol;bacque&period;biz&sol;wp-content&sol;uploads&sol;2014&sol;07&sol;20140711&lowbar;folderoption&lowbar;1&period;jpg&quest;fit&equals;660&percnt;2C608&amp&semi;ssl&equals;1" class&equals;"alignnone size-medium wp-image-2245" src&equals;"https&colon;&sol;&sol;bacque&period;biz&sol;wp-content&sol;uploads&sol;2014&sol;07&sol;20140711&lowbar;folderoption&lowbar;1-400x368&period;jpg" alt&equals;"20140711&lowbar;folderoption&lowbar;1" width&equals;"400" height&equals;"368" &sol;><&sol;a><&sol;p>&NewLine;<p>フォルダオプションを選択<&sol;p>&NewLine;<p><a href&equals;"https&colon;&sol;&sol;bacque&period;biz&sol;wp-content&sol;uploads&sol;2014&sol;07&sol;20140711&lowbar;folderoption&lowbar;2&period;jpg"><img data-attachment-id&equals;"2246" data-permalink&equals;"https&colon;&sol;&sol;bacque&period;biz&sol;archives&sol;2231&sol;20140711&lowbar;folderoption&lowbar;2" data-orig-file&equals;"https&colon;&sol;&sol;i0&period;wp&period;com&sol;bacque&period;biz&sol;wp-content&sol;uploads&sol;2014&sol;07&sol;20140711&lowbar;folderoption&lowbar;2&period;jpg&quest;fit&equals;801&percnt;2C768&amp&semi;ssl&equals;1" data-orig-size&equals;"801&comma;768" data-comments-opened&equals;"1" data-image-meta&equals;"&lbrace;&quot&semi;aperture&quot&semi;&colon;&quot&semi;0&quot&semi;&comma;&quot&semi;credit&quot&semi;&colon;&quot&semi;&quot&semi;&comma;&quot&semi;camera&quot&semi;&colon;&quot&semi;&quot&semi;&comma;&quot&semi;caption&quot&semi;&colon;&quot&semi;&quot&semi;&comma;&quot&semi;created&lowbar;timestamp&quot&semi;&colon;&quot&semi;0&quot&semi;&comma;&quot&semi;copyright&quot&semi;&colon;&quot&semi;&quot&semi;&comma;&quot&semi;focal&lowbar;length&quot&semi;&colon;&quot&semi;0&quot&semi;&comma;&quot&semi;iso&quot&semi;&colon;&quot&semi;0&quot&semi;&comma;&quot&semi;shutter&lowbar;speed&quot&semi;&colon;&quot&semi;0&quot&semi;&comma;&quot&semi;title&quot&semi;&colon;&quot&semi;&quot&semi;&rcub;" data-image-title&equals;"20140711&lowbar;folderoption&lowbar;2" data-image-description&equals;"" data-image-caption&equals;"" data-medium-file&equals;"https&colon;&sol;&sol;i0&period;wp&period;com&sol;bacque&period;biz&sol;wp-content&sol;uploads&sol;2014&sol;07&sol;20140711&lowbar;folderoption&lowbar;2&period;jpg&quest;fit&equals;400&percnt;2C383&amp&semi;ssl&equals;1" data-large-file&equals;"https&colon;&sol;&sol;i0&period;wp&period;com&sol;bacque&period;biz&sol;wp-content&sol;uploads&sol;2014&sol;07&sol;20140711&lowbar;folderoption&lowbar;2&period;jpg&quest;fit&equals;660&percnt;2C632&amp&semi;ssl&equals;1" class&equals;"alignnone size-medium wp-image-2246" src&equals;"https&colon;&sol;&sol;bacque&period;biz&sol;wp-content&sol;uploads&sol;2014&sol;07&sol;20140711&lowbar;folderoption&lowbar;2-400x383&period;jpg" alt&equals;"20140711&lowbar;folderoption&lowbar;2" width&equals;"400" height&equals;"383" &sol;><&sol;a><&sol;p>&NewLine;<p>「表示」タグを選択<&sol;p>&NewLine;<p><a href&equals;"https&colon;&sol;&sol;bacque&period;biz&sol;wp-content&sol;uploads&sol;2014&sol;07&sol;20140711&lowbar;folderoption&lowbar;3&period;jpg"><img data-attachment-id&equals;"2243" data-permalink&equals;"https&colon;&sol;&sol;bacque&period;biz&sol;archives&sol;2231&sol;20140711&lowbar;folderoption&lowbar;3" data-orig-file&equals;"https&colon;&sol;&sol;i0&period;wp&period;com&sol;bacque&period;biz&sol;wp-content&sol;uploads&sol;2014&sol;07&sol;20140711&lowbar;folderoption&lowbar;3&period;jpg&quest;fit&equals;458&percnt;2C448&amp&semi;ssl&equals;1" data-orig-size&equals;"458&comma;448" data-comments-opened&equals;"1" data-image-meta&equals;"&lbrace;&quot&semi;aperture&quot&semi;&colon;&quot&semi;0&quot&semi;&comma;&quot&semi;credit&quot&semi;&colon;&quot&semi;&quot&semi;&comma;&quot&semi;camera&quot&semi;&colon;&quot&semi;&quot&semi;&comma;&quot&semi;caption&quot&semi;&colon;&quot&semi;&quot&semi;&comma;&quot&semi;created&lowbar;timestamp&quot&semi;&colon;&quot&semi;0&quot&semi;&comma;&quot&semi;copyright&quot&semi;&colon;&quot&semi;&quot&semi;&comma;&quot&semi;focal&lowbar;length&quot&semi;&colon;&quot&semi;0&quot&semi;&comma;&quot&semi;iso&quot&semi;&colon;&quot&semi;0&quot&semi;&comma;&quot&semi;shutter&lowbar;speed&quot&semi;&colon;&quot&semi;0&quot&semi;&comma;&quot&semi;title&quot&semi;&colon;&quot&semi;&quot&semi;&rcub;" data-image-title&equals;"20140711&lowbar;folderoption&lowbar;3" data-image-description&equals;"" data-image-caption&equals;"" data-medium-file&equals;"https&colon;&sol;&sol;i0&period;wp&period;com&sol;bacque&period;biz&sol;wp-content&sol;uploads&sol;2014&sol;07&sol;20140711&lowbar;folderoption&lowbar;3&period;jpg&quest;fit&equals;400&percnt;2C391&amp&semi;ssl&equals;1" data-large-file&equals;"https&colon;&sol;&sol;i0&period;wp&period;com&sol;bacque&period;biz&sol;wp-content&sol;uploads&sol;2014&sol;07&sol;20140711&lowbar;folderoption&lowbar;3&period;jpg&quest;fit&equals;458&percnt;2C448&amp&semi;ssl&equals;1" class&equals;"alignnone size-medium wp-image-2243" src&equals;"https&colon;&sol;&sol;bacque&period;biz&sol;wp-content&sol;uploads&sol;2014&sol;07&sol;20140711&lowbar;folderoption&lowbar;3-400x391&period;jpg" alt&equals;"20140711&lowbar;folderoption&lowbar;3" width&equals;"400" height&equals;"391" &sol;><&sol;a><&sol;p>&NewLine;<p>「詳細設定」で登録されている拡張子は表示しないのチェックをはずす<br &sol;>&NewLine;＞OKボタンを押す<&sol;p>&NewLine;<p>以上で拡張子がすべて表示されるようになります。<&sol;p>&NewLine;