Batch Convert Images Free — JPG, PNG, WebP, HEIC | MiOffice
Convert multiple images at once between JPG, PNG, WebP, HEIC, and more. Batch processing in your browser. No upload, 5 shared daily eligible local uses; AI/cloud use credits.
Access and pricing
Supported tools include 5 free on-device uses per day, shared across eligible tools. On compatible devices, guest access needs no sign-in. Signed-in users also get 5 daily eligible on-device uses. AI and cloud processing use credits separately.
New accounts can claim 20 welcome credits once. Eligible offers in MiOffice can earn up to 80 reward credits; offer conditions apply.
Starter costs $6.99/month and includes 250 credits at each paid renewal plus unlimited eligible local processing. Unused credits roll over. The $2.99 Day Pass covers 24 hours of eligible local processing; AI and cloud credits are separate.
Compare tools using a representative file and inspect the export. Check supported formats, device compatibility, processing location and the displayed cost before starting. This article is published by MiOffice; consider its recommendations with that affiliation in mind.
Access and pricing updated October 30, 2026. This editorial update does not indicate a new test run.
Why Batch Convert Images?
Converting images one at a time is tedious when you have dozens or hundreds of files. Common scenarios that require batch conversion: transferring iPhone photos (HEIC) to a format your Windows PC or web service accepts (JPG), converting PNG screenshots to JPG for smaller email attachments, preparing images for a website in WebP format, or standardizing a mixed collection of formats for a project.
The MiOffice image converter handles batch conversion directly in your browser. Drop multiple files, select the output format, and download everything. No account, no file upload, no watermarks, no per-file limits.
How to Batch Convert Images (4 Steps)
Open the Image Converter
Go to the MiOffice image converter. The tool loads in your browser — no download or sign-up required.
Drop Multiple Images
Drag and drop all the images you want to convert. You can select multiple files at once from your file browser. The tool accepts mixed formats — you can drop HEIC, PNG, JPG, WebP, BMP, and TIFF files all in the same batch.
Select the Output Format
Choose your target format: JPG, PNG, WebP, AVIF, BMP, or TIFF. Adjust the quality slider if available (for lossy formats like JPG and WebP). All files in the batch will be converted to the same output format.
Download All Converted Images
Download individual files or grab everything at once. For large batches, files are bundled into a ZIP archive for easy download. All processing happens on your device — files stay on your device.
Convert your images now
Batch convert between JPG, PNG, WebP, HEIC, and more — free, no upload, 5 shared daily eligible local uses; AI/cloud use credits.
Open Image Converter FreeSupported Image Formats
| Format | Type | Best For | Transparency |
|---|---|---|---|
| JPEG / JPG | Lossy | Photos, email, universal sharing | No |
| PNG | Lossless | Screenshots, graphics, logos | Yes |
| WebP | Both | Web optimization, smaller file sizes | Yes |
| HEIC | Lossy | iPhone photos (Apple default) | No |
| BMP | Lossless | Legacy software, Windows apps | No |
| TIFF | Lossless | Print, archival, professional editing | Yes |
| AVIF | Lossy | Next-gen web (best compression) | Yes |
When to Batch Convert: Common Scenarios
HEIC from iPhone to JPG for Sharing
iPhones use HEIC format by default since iOS 11. While HEIC offers excellent compression, many Windows PCs, Android devices, older email clients, and web services do not support it. Batch converting your iPhone photo exports to JPG ensures universal compatibility. Set quality to 90% for excellent results with reasonable file sizes.
PNG Screenshots to JPG for Email
Screenshots saved as PNG can be 3-8 MB each. When you need to email multiple screenshots (bug reports, documentation, project updates), converting to JPG at 85% quality typically reduces each file to 200 KB - 1 MB with no meaningful visual difference. See our file size reduction guide for more tips.
JPG to WebP for Web Optimization
If you manage a website or blog, converting your image library from JPG to WebP reduces page load times significantly. WebP files are typically 25-35% smaller than JPEG at equivalent visual quality. This directly improves Core Web Vitals scores and SEO ranking. All modern browsers support WebP.
Standardizing Mixed Format Collections
Photo collections often contain a mix of formats from different cameras, phones, and downloads. Batch converting everything to a single format (typically JPG for photos or PNG for graphics) simplifies management, ensures compatibility, and makes it easier to organize and share your collection.
Quality and File Size Trade-offs
When converting to lossy formats (JPEG, WebP), the quality setting determines the balance between file size and image fidelity:
| Quality Setting | File Size Reduction | Visual Quality | Best For |
|---|---|---|---|
| 95-100% | Minimal (10-20%) | Near-identical to original | Archival, professional printing |
| 80-90% | Good (50-70%) | Excellent (imperceptible loss) | General use, email, sharing |
| 60-79% | Significant (70-85%) | Good (minor artifacts on zoom) | Web thumbnails, social media |
| Below 60% | Maximum (85-95%) | Noticeable quality loss | Previews only |
Recommendation: Use 85% quality for most batch conversions. This provides the best balance of file size reduction and image quality for sharing, email, and web use. Only go higher (95%+) for professional printing or archival purposes.
Privacy: Your Images Never Leave Your Device
Most online image converters upload your files to their servers for processing. MiOffice converts images entirely in your browser using Canvas API and WebAssembly. Your photos — personal, family, business, or otherwise — stay on your device throughout the entire process.
This is especially important for batch operations. When you convert 50 photos at once, those 50 images never touch any external server. No data leaves your browser. No account is needed. No tracking of what you convert.
Related Guides
Convert Your File Now
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Frequently Asked Questions
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Jay Padimala
CEO & Founder
Jay Padimala is CEO and Founder of MiOffice, a product of JSVV SOLS LLC.
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