It has been suggested that setting inline width and height for images can benefit SEO and improve site loading speed.
Indeed, historically this has been the case, particularly in terms of faster website loading times.
By defining the height and width attributes of an <img> element, the browser can allocate a space with those specific dimensions for the image while it continues to process the rest of the HTML document. This results in a smoother rendering process as the browser already knows where to place the image without needing to make adjustments after loading it.
This proactive approach to sizing enhances the overall rendering speed.
In comparison, if the width and height attributes are not specified, the browser must wait until the image is fully downloaded before determining its size, leading to potential reflows of the document and slowing down the rendering process.
Consider a scenario with 50 images lacking defined width and height attributes - the impact on performance could be significant.
The concept outlined above reflects the more traditional perspective on image loading.
However, there are opposing viewpoints suggesting that for responsive design, avoiding width and height attributes may be beneficial.
In Responsive Design, width or height attributes are typically omitted
Many responsive websites opt out of specifying width or
height to allow images to adjust to varying screen sizes. Using fixed dimensions with <img> might hinder user experience, which Google considers crucial.
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Both arguments have merit, and the most suitable approach depends on individual circumstances. Before making a decision, here are some additional resources to consider:
- Benefits of Specifying Image Dimensions for Browser Performance
- Choosing Between Image Width/Height Attributes or CSS Styling