Every image, font, and script uses some of the visitor’s data, device capacity, or waiting time. A design decision should therefore consider both what an addition communicates and what it costs as part of the whole page.
Spend on what helps people understand.
A page can gain a second font, a large background image, and an animation library through three individually reasonable decisions. Together they may burden a visitor on a limited connection. Reviewing the combined experience reveals costs that isolated approvals miss. The graphic joins separate additions into one cumulative bar. A second bar gives more room to useful artwork detail and less to supporting elements. The proportions illustrate how a team might allocate its resources; they do not represent measured download times or results from a particular site.
Choose limits that fit the audience and the purpose of the page, then measure against those limits. A large artwork image may need more data to show its detail, while an unused effect adds data without helping the visitor. Spend the available time and bandwidth on what helps someone understand the work. An arbitrary size limit can also make the page less useful. Compressing artwork until its defining detail disappears saves bytes while weakening communication. Establish what needs to remain visible, then choose an appropriate size, format, and delivery strategy and measure the result.
Put it into practice.
Measure the complete page under conditions that resemble its audience. Review images, fonts, scripts, response time, and caching together. Use data and processing time for the detail people need, remove unused files or code, and review the total when another library or asset is proposed.
Which addition helps the visitor enough to justify the time it takes to load?