Batch Image Resizer
Resize many images and download a ZIP
Batch Image Resizer — what it does
Resize many images at once with three modes: fit inside a bounding box, force an exact size, or scale by width only and let height follow. Set a target width and height plus an output quality, and the whole set is re-rendered and packed into a ZIP, ready for upload limits that reject oversized files.
When this tool helps
- Meeting a platform's pixel cap — marketplaces and job boards routinely reject anything above a set width.
- Producing consistent thumbnails from photos that arrived in a mix of portrait and landscape orientations.
- Cutting the resolution of phone photos, where an 8-megapixel original is many times more than a web page needs.
How to use it
- Select the images to resize.
- Enter the target width and height.
- Choose a resize mode: fit inside, exact size or width only.
- Set output quality and download the ZIP.
Accuracy, limits, and good practice
- Fit inside preserves the aspect ratio and is what you want for mixed orientations; exact size will distort images that do not match the ratio.
- Enlarging beyond the original resolution produces a soft result — browsers interpolate pixels, they cannot invent detail.
- Width-only mode is the safest choice for a gallery, since every image ends at the same column width with its proportions intact.
Frequently asked questions
Which mode keeps proportions?
Both fit inside and width only. Exact size stretches the image to the dimensions you typed regardless of the original ratio.
Does resizing also reduce file size?
Yes, substantially. Halving both dimensions removes about three quarters of the pixels, and the encoded file shrinks accordingly.
How many images can I process at once?
Dozens are routine. Very large batches of high-resolution files can exhaust the tab's memory, so split them into smaller groups.
Related tools on this site
- Image Color Picker — Click an image to identify HEX and RGB colors
- Image Opacity Tool — Adjust image transparency and export as PNG
- Sprite Sheet Generator — Arrange multiple images into a downloadable PNG sprite sheet
Everything above runs inside this page. Batch Image Resizer needs no account, no upload, and no server round trip — close the tab and nothing is left behind.
批量調整圖片尺寸能做什麼
一次縮放多張圖片，提供三種模式：限制在指定框內、強制指定尺寸，或只依寬度縮放讓高度自動跟隨。設定目標寬高與輸出品質後，整組圖片會重新算圖並打包成 ZIP，正好應付會擋大檔的上傳限制。
什麼時候用得上
- 符合平台的像素上限：拍賣網站與求職平台常會直接退回超過指定寬度的圖片。
- 從直式與橫式混雜的照片中，產出尺寸一致的縮圖。
- 降低手機照片解析度，八百萬像素的原檔遠超過網頁實際所需。
使用步驟
- 選擇要縮放的圖片。
- 輸入目標寬度與高度。
- 選擇縮放模式：限制框內、指定尺寸或僅依寬度。
- 設定輸出品質並下載 ZIP。
精確度、限制與實務建議
- 「限制框內」會維持長寬比，適合直橫混雜的檔案；「指定尺寸」則會把比例不符的圖片拉變形。
- 放大超過原解析度會變糊，瀏覽器只能內插像素，無法憑空生出細節。
- 做圖庫時「僅依寬度」最安全，所有圖片都會落在同一欄寬且比例不變。
常見問題
哪個模式會保持比例？
「限制框內」與「僅依寬度」都會。「指定尺寸」則不論原始比例，直接拉成你輸入的寬高。
縮放也會讓檔案變小嗎？
會，而且相當明顯。寬高各減半約可去掉四分之三的像素，編碼後的檔案也會跟著縮小。
一次可以處理幾張？
數十張是常態。高解析度檔案的超大批次可能耗盡分頁記憶體，建議分批處理。
本站相關工具
以上步驟全部在這個頁面內完成，批量調整圖片尺寸 不需要註冊、不上傳檔案、也不經過伺服器，關閉分頁後不會留下任何資料。