If you want to keep transparent parts, save as PNG or WebP. JPEG cannot have transparency, so it will be filled with the background color during conversion. Check whether it just looks black or whether it was actually saved as black.
Transparency is information, not color.
The reason why a PNG background looks transparent is not because the background color is white. Each pixel contains transparency information, and its appearance changes depending on the app and background you display it on.
Transparent parts may appear black in apps with dark screens. If the image is normal when placed on a different white background, it is not a broken image, but a difference in display.
Transparency disappears when set to JPEG
JPEG format cannot preserve transparency. Therefore, when converting from PNG to JPEG, it is necessary to fill the transparent parts with white, black, or another specified color. Check the background color settings of the conversion tool.
PNG is suitable for images that will be overlaid on another background later, such as logos, stamps, and cutouts. JPEG and WebP are suitable if you only want to save photos lightly.
Safe Selection by Purpose
Logos whose background may change depending on the website or material are PNG. JPEGs for email attachments and photo sharing. WebP is a candidate for web applications where you want to reduce capacity while maintaining transparency.
However, older software or submission services may not accept WebP. If there is a format specified by the other party, adapt to that format.
- Leave transparency: PNG/WebP
- Lighten photos: JPEG/WebP
- Prefer compatibility: JPEG/PNG
Always check after conversion
Opening the saved image on both a white background and a dark background makes it easier to notice residual transparency and edge color. When cutting out people or products, zoom in to make sure there are no black edges left in the outline.
Confirmation after format conversion
- ✓Determined the need for transparency
- ✓Selected the format supported by the submission destination
- ✓I checked the appearance on a white/dark background
- ✓I left the original PNG separately
画像形式変換
You can select JPEG, PNG, or WebP and check the background color of transparent parts before converting.
画像形式変換→This article gives general guidance. If a recipient, printer or official service provides its own requirements, follow those requirements first.
A SMALL NOTE FROM SPACETransparency is not ``nothing'', but information that is properly preserved. Choose a format that is unmistakable to the darkness of space.