Бесплатное преобразование изображений в браузере
JPG to PNG Converter
ImageConver converts a JPG or JPEG into PNG in your browser by decoding the JPEG and writing the pixels as image/png. PNG avoids another lossy encoding step for the converted raster, but it cannot restore JPEG detail that was already discarded or recreate the source file original transparency. PNG can be larger for photos. An optional color-key transparency workflow uses a tolerance value, which can affect nearby foreground colors. Your image contents stay in the browser and are not uploaded.
Бесплатный инструмент для браузера
Convert and inspect the PNG output
Выберите одно изображение, выберите соответствующие настройки и сравните результат перед загрузкой. Содержимое изображения остается в этом рабочем процессе браузера.
- Изменение размера
- –
- Фоновая обработка
- Not applied
Для начала выберите исходное изображение.
С первого взгляда
Quick facts for JPG to PNG conversion
- Ввод MIME
- изображение/jpg.
- Input extensions
- .jpg and .jpeg; both are common filename endings for the JPEG media type.
- Input compression
- JPEG is normally lossy, so the decoded pixels may already include compression artifacts.
- Выходной MIME
- изображение/png.
- Сжатие PNG
- PNG is lossless in the format specification for the pixels it receives, but that does not recover detail lost in the source JPEG.
- Прозрачность
- A normal JPG to PNG conversion does not recreate original transparency. Optional color-key removal can make selected pixels transparent using a tolerance.
- Анимация
- JPG and PNG are single-image formats in this workflow; there is no animation to preserve.
Рабочий процесс
How to convert JPG to PNG
- 1
Select a JPG or JPEG
Choose the source photo, scan, screenshot, or graphic. The browser decodes the JPEG pixels; this does not expose the original pre-compression data.
- 2
Choose transparency behavior
Leave pixels opaque for a faithful canvas export, or enable the optional color-key workflow only when a known background color should become transparent.
- 3
Set tolerance carefully
A small tolerance selects colors close to the key color. Increase it only while checking edges, because nearby foreground pixels can also be cleared.
- 4
Inspect and download
Compare the PNG against the JPG at full size, check the alpha edge if used, and confirm that the larger PNG fits the target editor or upload limit.
Элементы управления
JPG to PNG settings explained
- PNG output
- Canvas toBlob accepts an output MIME and a quality argument for lossy image types. This request uses image/png, so the PNG encoding does not add another JPEG-style quality loss, but it records the pixels that the browser decoded from the JPG.
- Color-key transparency
- When enabled, pixels near a chosen key color can have their alpha cleared. This is useful for simple solid backgrounds, not for complex photographic separation.
- Tolerance
- Tolerance is a color-distance threshold. A higher value affects a wider range of nearby colors and can remove similar foreground shades along with the background.
- Output filename
- The download uses a PNG extension so applications can identify the new MIME type. It does not imply that original JPEG metadata or detail has been restored.
Выходное поведение
What JPG to PNG can and cannot change
Another lossy step is avoided
Writing the decoded pixels as PNG avoids another JPEG encoding step. This can help when the PNG will receive more edits, text overlays, or repeated saves, but it cannot restore detail that the source JPEG already lost.
Original transparency cannot be restored
A JPG has no alpha channel. The converter cannot know which background pixels were once transparent. Optional color-key removal is an inference based on a selected color and tolerance, not recovery of original transparency.
Photos often grow in size
PNG can be larger than JPG for photographs because PNG preserves each received pixel without JPEG quantization. A larger file is expected in many photo cases and is not by itself a conversion error.
Tolerance can change foreground colors
Color-key transparency compares pixel colors to a key color. Anti-aliased edges and similarly colored objects can be affected when tolerance is too high, so inspect the result against a contrasting background.
Руководство по принятию решений
When JPG to PNG is worth doing
Convert to PNG when the next tool needs PNG input, when you need to avoid another lossy JPEG save, or when you will add overlays and want an alpha-capable output canvas for new pixels. Start with the default opaque export when you want the decoded image without an unverified background removal.
Do not convert expecting sharper original detail or recovered transparency. Keep the JPG for compact photo delivery, and use the color-key option only for a simple, known background where you can review edge effects. For photographs, compare file sizes before committing to PNG storage.
Сравнивать
Opaque export versus color-key transparency
| Mode | Keeps | Useful For | Watch For |
|---|---|---|---|
| Opaque PNG | All decoded pixels as visible pixels | Photo archives, editors, and predictable visual comparison | No alpha is invented; the file can be larger than the JPG |
| Color-key PNG | Pixels outside the selected color range | Simple flat backgrounds and basic cutout preparation | Tolerance can remove similar foreground colors and create edge artifacts |
| Keep JPG | The original compressed delivery file | Compact photo publishing and systems that require JPEG | Further JPEG saves can add more lossy artifacts |
Решение проблем
Troubleshooting JPG to PNG output
The PNG looks no sharper than the JPG
Вероятная причина: PNG cannot restore detail that JPEG compression already discarded.
Что делать: Use the original camera or source export when detail matters. Treat JPG to PNG as a format change, not an enhancement step.
The PNG is much larger
Вероятная причина: PNG preserves the decoded pixels and is often less compact for photos.
Что делать: Keep JPG for compact photo delivery, or compare PNG size against the editing or upload requirement before storing it.
The result is not transparent
Вероятная причина: A normal conversion does not know which JPG pixels should have alpha.
Что делать: Use a color-key workflow only for a known background, then verify the alpha edge. Original transparency cannot be reconstructed from an ordinary JPG.
Foreground colors disappeared
Вероятная причина: The selected color-key tolerance covered colors similar to the background.
Что делать: Lower tolerance, choose a more representative key color, or leave the export opaque and remove the background with a dedicated editing workflow.
Конфиденциальность
Browser-local JPG processing
The source image stays in your browser while the JPEG is decoded and converted with canvas APIs. The page may load its own scripts and normal site assets, but this workflow does not upload image contents to a conversion server.
Local processing does not promise that the output contains no identifying information: the source pixels may show people or places, and canvas output can omit or change metadata. Review the visual file and your sharing context before publishing it.
- Обработка исходного кода
- Image contents stay in the browser during decoding, color-key processing, and PNG encoding.
- Metadata handling
- Do not rely on source JPEG metadata being preserved through canvas output.
Общие вопросы
JPG to PNG questions
Does JPG to PNG restore lost detail?
No. PNG avoids another lossy encoding step, but it cannot restore JPEG detail that was already discarded.
Can the converter recover original transparency?
No. JPG has no alpha channel. A color-key option can infer transparency from a selected color and tolerance, but it cannot know the original mask.
Why is the PNG larger than the JPG?
PNG can be larger for photos because it preserves the decoded pixel values without JPEG quantization. This is common and not automatically a failure.
What does tolerance do?
Tolerance sets how far a pixel color may be from the selected key color and still be cleared. Higher tolerance can affect similar foreground colors.
Should I use color-key transparency on a photo?
Only when the background is simple and close to a known color. Textured backgrounds, shadows, and similar subject colors can produce visible edge artifacts.
Is the source JPEG uploaded?
При преобразовании содержимое изображений сохраняется в браузере и не загружается на сервер преобразования, хотя страница может загружать свои собственные скрипты и ресурсы.
Will PNG preserve my JPEG metadata?
Do not assume so. Canvas conversion can omit source metadata, so keep the original JPEG when those fields are needed.
Ссылки