Qt 支持的图片格式如下：
| Format | Description | Qt's support |
|---|---|---|
| BMP | Windows Bitmap | Read/write |
| GIF | Graphic Interchange Format (optional) | Read |
| JPG | Joint Photographic Experts Group | Read/write |
| JPEG | Joint Photographic Experts Group | Read/write |
| PNG | Portable Network Graphics | Read/write |
| PBM | Portable Bitmap | Read |
| PGM | Portable Graymap | Read |
| PPM | Portable Pixmap | Read/write |
| TIFF | Tagged Image File Format | Read/write |
| XBM | X11 Bitmap | Read/write |
| XPM | X11 Pixmap | Read/write |
OpenCV 支持的图片格式如下：
Windows bitmaps - *.bmp, *.dib (always supported)
JPEG files - *.jpeg, *.jpg, *.jpe (see the Notes section)
JPEG 2000 files - *.jp2 (see the Notes section)
Portable Network Graphics - *.png (see the Notes section)
Portable image format - *.pbm, *.pgm, *.ppm (always supported)
Sun rasters - *.sr, *.ras (always supported)
TIFF files - *.tiff, *.tif (see the Notes section)下面是1024X768分辨率的图片在各种格式下的尺寸，参见这里。
| 图片格式 | 色彩位数 | 图片质量 | 文件大小（KB） | 备注 |
| bmp | 8 | - | 769 | - |
| bmp | 24 | - | 2359 | - |
| jpg | - | 0% | 104 | - |
| jpg | - | 25% | 124 | - |
| jpg | - | 50% | 156 | - |
| jpg | - | 75% | 220 | - |
| jpg | - | 100% | 639 | - |
| gif | 8 | - | 225 | - |
| tiff | - | - | 1880 | - |
| png | - | - | 868 | 用ACDSEE保存 |
| png | 1 | - | 73 | 用PhotoShop保存 |
| png | 6 | - | 194 | 用PhotoShop保存 |
| png | 7 | - | 267 | 用PhotoShop保存 |
| png | 8 | - | 332 | 用PhotoShop保存 |
| png | 24 | - | 895 | 用PhotoShop保存 |
从上表可以看出，jpg格式在图片大小和质量之间得到了很好的平衡；即使选择0%的图片质量，仍然可以接受，而图片大小只有104KB。