當你需要無損格式用於編輯、圖形或透明度時，將 JPG（JPEG）圖片轉換為 PNG。PNG 非常適合標誌、螢幕截圖以及具有銳利邊緣的圖片。
一切都在你的裝置上本地進行 — 你的圖片永遠不會被上傳到伺服器。
如何使用此工具
新增你的 JPG
將你的 JPG 拖曳到工具上，或按一下選擇檔案。
已預先選取 PNG
輸出已設定為無損 PNG，因此不會重新壓縮任何內容。
預覽結果
並排比較原始圖片與轉換後的 PNG。
下載
下載你高品質的 PNG 檔案。
本節目前僅提供英文版本。
What this conversion can and cannot do
Converting JPEG to PNG is lossless in the sense that no further quality is lost: every pixel of the JPEG is stored exactly. What it cannot do is recover what the JPEG already threw away. The blockiness and ringing in a heavily compressed JPEG are part of the image now, and a PNG will preserve them faithfully.
This is the most common misconception in image conversion, so it is worth stating plainly: **a JPEG converted to PNG is a large file with JPEG quality.** It does not become a better image.
The one good reason to do it
Editing. If you need to open the image in an editor, cut something out of it, or composite it with other artwork, PNG is the right working format — repeated saves will not degrade it further the way repeated JPEG saves would. Convert to PNG, do the work, then export back to an efficient delivery format at the end.
If what you actually want is transparency
JPEG cannot store transparency, so converting to PNG does not create any — the background pixels are whatever colour they were, and you have to remove them yourself. Tools that claim to add transparency while converting are really running a background-removal step, which is a different operation with its own accuracy limits.
常見問題
為什麼要把 JPG 轉成 PNG？
PNG 是無損的且支援透明度，非常適合標誌、螢幕截圖，以及需要在無損品質下編輯的圖片。
轉換是無損的嗎？
是的 — 輸出編碼為無損 PNG，因此轉換過程中不會損失額外的品質。
PNG 會比 JPG 大嗎？
通常會，因為 PNG 是無損的，而 JPG 是有損的。這是預期中的取捨 — 你以大小換取品質和透明度。