Summary
Optimizing image file size for emails is critical for deliverability, loading times, and user experience. Experts and marketers recommend balancing image quality with file size by using appropriate file formats (JPEG, PNG, WebP), compressing images, and resizing them to fit the display area. While some suggest an overall email size of under 100KB to avoid Gmail clipping, others aim for under 500KB or even allow up to 2MB. Using CDNs, lazy loading, and tools like TinyPNG/ImageOptim are also advised. Key considerations include responsive design, testing across email clients, and understanding the impact of file size on carbon footprint.
Key findings
- File Format: Use JPEG for photos, PNG for graphics with transparency, and consider WebP for enhanced compression.
- Compression: Compress images to reduce file size without significant quality loss using tools like TinyPNG or ImageOptim.
- Total Email Size: Target a total email size (HTML, images, text) under 100KB-500KB to avoid clipping and ensure fast loading; 102KB to avoid Gmail clipping.
- Deliverability Impact: Large images and overall email size can trigger spam filters and negatively impact sender reputation.
- Loading Time: Optimized images and smaller overall size significantly improve email loading times.
Key considerations
- Image Dimensions: Resize images to match the intended display area to minimize file size.
- Responsive Design: Implement responsive design techniques and provide smaller image options for mobile devices.
- Testing: Thoroughly test emails across different email clients and devices to ensure proper display and functionality.
- CDN and Lazy Loading: Consider using a Content Delivery Network (CDN) to host images and implement lazy loading to improve loading times.
- Optimize for Region: If sending worldwide, consider further optimizing or removing frames to accommodate varying internet speeds.
What email marketers say
11 marketer opinions
Optimizing image file size for emails is crucial for avoiding spam filters, ensuring fast loading times, and improving overall deliverability. Best practices include using appropriate file formats (JPEG for photos, PNG for graphics), compressing images to reduce file size, and resizing images to fit the intended display area. Keeping the total email size (including HTML and images) under 100KB-500KB is recommended to prevent clipping and improve the user experience. Load time and carbon footprint are also factors to consider. CDNs, lazy loading, and image optimization tools can also aid in creating optimized emails.
Key opinions
- File Format Matters: Use JPEG for photos and PNG for graphics to optimize image quality and file size.
- Compression is Key: Compress images to reduce file size without sacrificing too much quality. Tools like TinyPNG and ImageOptim can help.
- Total Email Size: Aim to keep the total email size (HTML, images, text) under 100KB-500KB to avoid clipping and improve loading times. Although some suggest up to 2MB is ok.
- Deliverability Impact: Optimizing images improves deliverability and sender reputation, preventing emails from landing in the spam folder.
- Responsive Design: Create responsive versions of images that load faster on mobile devices.
Key considerations
- Image Dimensions: Resize images to fit their intended display area to prevent unnecessary file size.
- Testing: Test emails with different image sizes and email clients to ensure optimal display and deliverability.
- CDN: Consider using a Content Delivery Network (CDN) to host images for faster loading times.
- Lazy Loading: Consider lazy loading of images in your emails
- Balance Quality and Size: Balance image quality with file size to ensure a good user experience without compromising deliverability.
Marketer view
Email marketer from Quora user Jane Doe explains that images should be optimized to be as small as possible without sacrificing visual quality. She notes that using tools for compression and adjusting dimensions can significantly reduce file size and improve email loading times.
17 Aug 2023 - Quora
Marketer view
Email marketer from HubSpot responds that optimizing images through compression and using appropriate dimensions is crucial for email deliverability. Reducing file size ensures faster loading and a better user experience, which can positively impact sender reputation and prevent emails from landing in the spam folder.
22 Sep 2021 - HubSpot
What the experts say
1 expert opinions
Laura Atkins from Word to the Wise emphasizes that image optimization is critical for email deliverability. Large images can trigger spam filters, and slow loading times can hurt engagement. Vital elements include appropriate file formats, compression, and resizing.
Key opinions
- Deliverability: Optimizing images is essential for email deliverability.
- Spam Filters: Large images can trigger spam filters.
- Engagement: Slow loading times negatively impact engagement.
Key considerations
- File Formats: Use appropriate file formats for images.
- Compression: Compress images to reduce file size.
- Resizing: Resize images appropriately.
Expert view
Expert from Word to the Wise, Laura Atkins, explains that optimizing images is essential for email deliverability. Large images can trigger spam filters, and slow loading times can negatively impact engagement. Using appropriate file formats, compression, and resizing images are all vital elements.
14 Aug 2021 - Word to the Wise
What the documentation says
6 technical articles
Multiple sources indicate that optimizing image file sizes is crucial for email deliverability and loading times. Gmail clips emails exceeding 102KB total size. While there's no single optimal size, aiming for under 1MB is generally recommended, but smaller is better. Choosing the right format (JPEG, PNG, or WebP) and using compression techniques are vital. Responsive images and proper resizing also contribute to performance. Consider using CSS instead of images where possible.
Key findings
- Gmail Clipping: Gmail clips emails larger than 102KB (total size).
- Format Matters: Choosing the right image format (JPEG, PNG, WebP) is critical for file size and quality.
- Compression: Image compression is essential to reduce file size.
- Performance Impact: Reducing image size improves loading times and user experience.
Key considerations
- Total Size Goal: Aim for under 1MB per email, but smaller is better (target around 100kb).
- Responsive Images: Use responsive images to adapt to different screen sizes.
- Resizing: Ensure images are appropriately sized for their display area.
- CSS vs Images: Consider using CSS instead of images where possible to reduce file size.
Technical article
Documentation from Microsoft provides some best practices that include compressing images, choosing the correct format (JPEG or PNG), and using the Picture Manager to resize your images to the desired dimensions. This helps reduce the size of your emails.
7 Nov 2021 - Microsoft Support
Technical article
Documentation from Email on Acid shares that while there's no single 'optimal' image size, aiming for under 1MB is a good starting point, but far smaller is better. They discuss how using optimized JPEG or PNG files, depending on the image type, and ensuring images are appropriately sized for their display area can improve deliverability and loading times.
1 Oct 2021 - Email on Acid
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